FreeRDP before 3.29.0 contains integer overflow vulnerabilities in the audio input redirection channel (audin) across ALSA, sndio, WinMM, and OpenSL ES backends that fail to validate the FramesPerPacket parameter from RDP servers. Attackers can supply a malicious FramesPerPacket value causing allocation size wraparound, resulting in heap-based buffer overflow on ALSA or denial of service on all platforms.

FreeRDP before 3.30.0 (<= 3.29.0) contains a heap-based buffer overflow in the Windows clipboard client's CliprdrStream_Read function (client/Windows/wf_cliprdr.c). When an OLE paste consumer (e.g. explorer.exe) calls IStream::Read with a fixed-size buffer of cb bytes, CliprdrStream_Read requests file contents from the RDP server and then copies the response into the caller's buffer using the server-supplied length (req_fsize) instead of cb. A malicious or compromised RDP server can return an oversized CB_FILECONTENTS_RESPONSE, causing an out-of-bounds write of attacker-controlled data into the paste consumer's heap buffer when a user pastes server-offered clipboard file contents.

FreeRDP versions 3.28.0 and earlier contain a heap buffer overflow in the server-side RAIL channel handler (rail_server_handle_messages() in channels/rail/server/rail_main.c). When processing a RAIL PDU header, the code subtracts RAIL_PDU_HEADER_LENGTH from the peer-controlled orderLength field without first verifying orderLength is at least the header length. For orderLength values 0..3 this causes an unsigned integer underflow to a very large size, which bypasses the Stream_EnsureRemainingCapacity() capacity check (due to pointer arithmetic wraparound) and is then passed to WTSVirtualChannelRead(), resulting in an out-of-bounds heap write. A malicious or compromised RDP client can exploit this to corrupt the heap and crash the server. Fixed in FreeRDP 3.29.0.

FreeRDP before 3.29.0 (affected versions <= 3.28.0) contains a heap out-of-bounds read in update_process_glyph_fragments()/glyph_cache_fragment_put() in libfreerdp/cache/glyph.c. When handling a GLYPH_FRAGMENT_ADD update, the code reads a one-byte server-controlled declared fragment size but does not verify it fits within the remaining received buffer before allocating and copying that many bytes. A malicious RDP server can send a short fragment with an oversized declared size, causing the client to read beyond the allocated buffer, resulting in an out-of-bounds read and client crash.

FreeRDP before 3.29.0 contains client-side heap use-after-free vulnerabilities in the async update message proxy for RAIL WINDOW_STATE_ORDER and NOTIFY_ICON_STATE_ORDER when AsyncUpdate is enabled. When a malicious or compromised RDP server sends crafted update orders, the message proxy shallow-copies structures containing nested parser-owned pointers (e.g., titleInfo.string, windowRects, visibilityRects, icon buffers). The parser frees those nested buffers after the callback returns, so the queued async message later dispatches stale pointers, potentially causing memory corruption or a client crash.

FreeRDP before 3.29.0 contains a client-side heap use-after-free in the async update message proxy for WINDOW_ICON_ORDER when AsyncUpdate is enabled (e.g. xfreerdp /async-update). In update_message_WindowIcon() a shallow CopyMemory() overwrites a freshly allocated lParam->iconInfo with the parser-owned windowIcon->iconInfo pointer. After the parser callback returns, update_recv_window_info_order() frees window_icon.iconInfo, but the queued async message still retains and later dispatches that stale pointer. A malicious or compromised RDP server sending a crafted RAIL Window Alternate Secondary Order with WINDOW_ORDER_ICON can trigger use-after-free, leading to memory corruption and client crash.

FreeRDP before 3.29.0 contains a null pointer dereference vulnerability in smartcard cache request decoders that accept NULL NDR pointers for LookupName in SCARD_IOCTL_READCACHEA and SCARD_IOCTL_WRITECACHEA operations. When smartcard emulation is enabled, attackers can send crafted smartcard cache requests with NULL lookup-name pointers to trigger strlen() on a null pointer, causing client process termination.

FreeRDP before 3.29.0 contains a reachable assertion (WINPR_ASSERT(OutputBufferLength == BytesReturned)) in serial_process_irp_device_control() in channels/serial/client/serial_main.c. When serial device redirection is enabled and a server-controlled IRP_MJ_DEVICE_CONTROL request specifies an unsupported IOCTL with a non-zero OutputBufferLength, CommDeviceIoControl() can fail with BytesReturned = 0, causing the mismatch to trigger the assertion and abort the client process (denial of service).

FreeRDP before 3.29.0 fails to properly validate server-supplied RDPDR paths in drive redirection, allowing attackers to access prefix-sibling paths outside the configured shared root. A malicious RDP server can read, write, delete, and enumerate files in sibling directories by sending non-rooted paths that bypass the shared-root boundary check.

FreeRDP before 3.29.0 contains a buffer over-disclosure vulnerability in the gateway WebSocket transport (libfreerdp/core/gateway/websocket.c). The client's Pong reply reuses a fixed 1024-byte response stream whose length is not sealed to the actual received Ping payload, so a malicious gateway/WebSocket peer sending a non-empty Ping control frame causes the client to reply with an overlong Pong that discloses bytes beyond the received payload (the peer receives the masking key and can unmask the reply). A zero-length Ping reaches an assertion and terminates the client (denial of service).

FreeRDP before 3.29.0 contains an out-of-bounds heap read vulnerability in the UVC H.264 extension-unit parser that fails to validate descriptor length before accessing the GUID field. A local attacker with a malicious USB video camera can trigger a heap read beyond allocated bounds during camera stream setup, causing denial of service.

FreeRDP before 3.29.0 (affected versions <= 3.28.0) contains a divide-by-zero vulnerability in the rdpecam camera redirection client. ecam_dev_process_start_streams_request() parses a server-controlled CAM_MEDIA_TYPE_DESCRIPTION from a StartStreamsRequest PDU but validates only Format and Flags, not FrameRateDenominator. When a malicious or compromised RDP server sends a StartStreamsRequest with FrameRateDenominator set to zero, ecam_encoder_context_init() (channels/rdpecam/client/encoding.c) computes FrameRateNumerator / FrameRateDenominator, causing an integer division by zero (SIGFPE) and termination of the FreeRDP client process. Camera redirection must be enabled on the client for the channel to be reachable. Fixed in FreeRDP 3.29.0.

FreeRDP versions 3.28.0 and earlier contain an out-of-bounds read vulnerability in the RDP6 planar RLE bitmap decoder functions planar_decompress_plane_rle and planar_decompress_plane_rle_only in libfreerdp/codec/planar.c. Only the 1-byte control byte is bounds-checked; the subsequent 0–15 attacker-declared raw bytes are read without validating that the source buffer contains them. A malicious or compromised RDP server can send a truncated planar-encoded bitmap or surface update (reachable via both the Bitmap Update PDU and RDPGFX Surface Command paths) that causes the client to read past the end of the source buffer. The issue is fixed in FreeRDP 3.29.0.

FreeRDP before 3.29.0 (affected versions <= 3.28.0) does not validate CRLF and control characters in the server-controlled RDP redirection TargetNetAddress field. This value is copied into the client's ServerHostname and, when the client connects through an HTTP proxy, is written directly into the proxy CONNECT request line and Host header by http_proxy_connect() without filtering. A malicious or compromised RDP server can send a crafted redirection PDU containing embedded control characters to inject arbitrary headers/requests into the HTTP proxy CONNECT request.

FreeRDP before 3.29.0 improperly validates the Extended Key Usage (EKU) purpose of the peer certificate during client-side server TLS authentication. In x509_utils_verify(), when server-purpose (X509_PURPOSE_SSL_SERVER) verification fails, the code falls back to client-purpose and any-purpose verification, so a trusted, hostname-matching certificate valid only for clientAuth can be accepted as the RDP server certificate. In environments relying on EKU separation between client and server certificates, this allows a clientAuth-only certificate issued by a trusted CA to bypass server certificate purpose validation.

FreeRDP before 3.29.0 contains a denial of service vulnerability in the RDPEI server channel handler that fails to validate maximum PDU body length before stream allocation. A malicious RDP client can send a header-only RDPEI message with a large declared body length to force excessive memory allocation on the server.

FreeRDP before 3.29.0 contains a null pointer dereference vulnerability in smartcard device control request cleanup when reader-state decoding fails. Attackers can send malformed smartcard IRP requests with non-zero cReaders and truncated reader-state data to crash the process via null pointer access in free_reader_states functions.

FreeRDP before 3.29.0 (affected versions <= 3.28.0) contains multiple TLS certificate identity validation weaknesses in tls_verify_certificate(), tls_match_hostname(), and x509_utils_get_dns_names(). Because FreeRDP performs custom Common Name and DNS SAN string matching instead of using OpenSSL's length-aware identity validation APIs, it (1) truncates DNS SAN values at embedded NUL bytes (accepting e.g. 'victim.example\0.attacker.example' as 'victim.example'), (2) accepts a matching Common Name even when non-matching DNS SAN entries are present, and (3) accepts IP-literal targets via DNS/CN matching without comparing iPAddress SANs. Under a trusted or misissued certificate chain, an attacker positioned to present such a certificate can bypass server identity verification, weakening TLS server authentication.

FreeRDP before 3.29.0 fails to enforce the RESPONSE_SIZE_LIMIT when processing Transfer-Encoding: chunked HTTP responses in http_response_recv_body(). Attackers controlling a malicious RD Gateway endpoint can send oversized chunked response bodies to exhaust client memory resources without triggering the configured size limit.

FreeRDP before 3.29.0 contains out-of-bounds read vulnerabilities in the async update message proxy for the PolygonSC and PolygonCB primary drawing orders. When AsyncUpdate is enabled (e.g., xfreerdp /async-update), update_message_PolygonSC() and update_message_PolygonCB() allocate a fresh points array but copy point data from the address of the order structure instead of from polygonSC->points / polygonCB->points, resulting in a client-side out-of-bounds read. A malicious or compromised RDP server sending crafted PolygonSC/PolygonCB update orders can trigger memory disclosure or a client crash.

FreeRDP before 3.29.0 (affected versions <= 3.28.0) contains an improper certificate hostname validation vulnerability. The TLS hostname matcher (tls_match_hostname() in libfreerdp/crypto/tls.c) treats a wildcard pattern such as *.example.com as matching any hostname ending in .example.com, so it incorrectly accepts a wildcard certificate for multi-label subdomains like a.b.example.com (which OpenSSL's X509_check_host() rejects). This weakens TLS server authentication under wildcard-certificate conditions.

FreeRDP Windows client before 3.29.0 contains a heap buffer overflow vulnerability in the clipboard virtual channel when processing CLIPRDR_FILE_CONTENTS_RESPONSE PDUs without validating the server-provided size against the destination buffer. A malicious RDP server can send a response with a data payload significantly larger than requested, causing arbitrary heap memory corruption that may enable remote code execution when a user performs a paste operation.

FreeRDP before 3.29.0 contains a heap out-of-bounds read vulnerability in the TSMF FFmpeg decoder when parsing AVC1 MPEG2VIDEOINFO media types with insufficient ExtraData. Attackers can send malformed media format data from a server to trigger a crash by reading fixed offsets without validating source buffer length.

FreeRDP before 3.28.0 treats lines beginning with forward slash in RDP files as raw command-line options, exposing the entire CLI parser surface to untrusted files. Attackers can craft malicious RDP files with /rdp2tcp, /cert:ignore, or /drive options to execute arbitrary commands, bypass certificate validation, or expose local filesystems without user interaction.

FreeRDP before 3.28.0 (affected 3.x through 3.27.1) contains a double-free vulnerability in freerdp_client_rdp_file_apply_to_settings() (client/common/file.c) when parsing the selectedmonitors field of a .rdp connection file. The MonitorIds array is allocated through the settings object, and a raw non-owning pointer to it is freed on the strtoul error path without clearing settings->MonitorIds, leaving it dangling; at teardown freerdp_settings_free() frees the same buffer again. An attacker who convinces a victim to open a crafted .rdp file with oversized monitor tokens can trigger a size-controlled double-free in any FreeRDP CLI client (xfreerdp/sdl-freerdp/wlfreerdp) in the default configuration.

FreeRDP before 3.28.0 (affected <=3.27.1) contains a heap-based buffer overflow in crypto_rsa_common() (libfreerdp/crypto/crypto.c). The function writes the modular-exponentiation result into the caller's output buffer via BN_bn2bin() and only afterward checks output_length > out_length, so out-of-bounds bytes are written before the bounds check. On the server side, when a client selects RDP Standard Security, the encrypted client random is decrypted into a fixed 32-byte buffer. Because the server publishes its RSA public key, an unauthenticated attacker can forge a ciphertext whose decrypted value is up to the full modulus length (e.g. 256 bytes for RSA-2048), overflowing the 32-byte heap buffer by up to ~224 attacker-controlled bytes pre-authentication, resulting in denial of service.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.28.0 on 32-bit builds, FreeRDP clients contain an integer overflow in update_read_delta_points in libfreerdp/core/orders.c when multiplying an attacker-controlled point count by sizeof(DELTA_POINT), allowing a malicious RDP peer to allocate an undersized heap buffer and then write beyond it during initialization. This issue is fixed in version 3.28.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.28.0, FreeRDP server implementations with the MS-RDPECAM camera device enumerator channel enabled scan attacker-supplied DeviceName and VirtualChannelName fields for a NUL terminator in channels/rdpecam/server/camera_device_enumerator_main.c and then dereference once past the scan bound, allowing a malicious RDP client to trigger a 1- to 2-byte out-of-bounds heap read. This issue is fixed in version 3.28.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. From 3.21.0 before 3.28.0, FreeRDP clients using the GFX pipeline contain an incomplete fix for CVE-2026-23530 in planar_decompress_plane_rle_only in libfreerdp/codec/planar.c, allowing a malicious RDP server to send a truncated RDPGFX_CMDID_WIRETOSURFACE_1 planar payload that reads one byte past the input buffer. This issue is fixed in version 3.28.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.1, FreeRDP clients launched with the non-default /cache:codec:rfx option pass desktop stride and height to RemoteFX decoding for Cache Bitmap V3 data while allocating bitmap->data only for the smaller DstWidth and DstHeight in gdi_Bitmap_Decompress, allowing a malicious RDP server to trigger a heap out-of-bounds write with attacker-controlled offset and content. This issue is fixed in version 3.27.1.

FreeRDP before 3.22.0 contains a use-after-free vulnerability in dvcman_channel_close and dvcman_call_on_receive due to improper synchronization of channel_callback access. A malicious RDP server can trigger a race condition by sending DYNVC_DATA and DYNVC_CLOSE messages concurrently, causing heap-use-after-free in the drdynvc client thread and potentially enabling remote code execution or denial of service.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.26.0, FreeRDP's planar bitmap decoder has an out-of-bounds heap write when decoding RLE planar data. In libfreerdp/codec/planar.c, freerdp_bitmap_decompress_planar() validates the X destination coordinate nXDst against the caller-provided destination stride (nDstStep) even when it is writing into the internal temp buffer pTempData. An attacker can bypass the check with a large nDstStep and a large nXDst, causing planar_decompress_plane_rle() to write past the end of pTempData. This vulnerability is fixed in 3.26.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.26.0, a malicious RDP client can trigger a heap-buffer-overflow write in FreeRDP's server-side clipboard (cliprdr) channel by sending a CB_CLIP_CAPS PDU with a too-small capabilitySetLength. This can crash the server process (remote DoS) and may be exploitable for code execution because it corrupts heap memory. This vulnerability is fixed in 3.26.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.26.0, FreeRDP's RDPEAR NDR parser accepts one non-null NDR pointer ref-id for multiple logical pointer fields without tracking the pointed object's expected NDR type or ownership. When the same ref-id is reused across two pointer fields, the parser assigns the same heap object to both output fields. The generic destructor later walks each field independently and destroys/frees both pointers. This causes a malicious-server-triggerable heap use-after-free / double-free in the FreeRDP client's RDPEAR authentication-redirection path. This vulnerability is fixed in 3.26.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.26.0, a malicious RDP server can trigger a heap-buffer-overflow write in the FreeRDP client by sending crafted RDPGFX PDUs. The bug is in gdi_CacheToSurface: it validates a destination rectangle that is clamped to UINT16_MAX, but then performs the copy using the original cacheEntry->width/height. This can cause a large out-of-bounds heap write and may lead to client crashes or code execution. This bug is reachable from a malicious RDP server, but only when the client has RDPGFX enabled. This vulnerability is fixed in 3.26.0.

FreeRDP before 3.26.0 contains a heap-buffer-overflow vulnerability in gdi_CacheToSurface that allows remote attackers to write out-of-bounds heap memory. The vulnerability occurs because rectangle validation clamps coordinates to UINT16_MAX but performs copy operations using unclamped cache entry dimensions, enabling malicious RDP servers to trigger large out-of-bounds writes and potentially achieve remote code execution or client crash.

FreeRDP is a free implementation of the Remote Desktop Protocol. Versions prior to 3.25.0 have an off-by-one in the path traversal filter in `channels/drive/client/drive_file.c`. The `contains_dotdot()` function catches `../` and `..\` mid-path but misses `..` when it's the last component with no trailing separator. A rogue RDP server can read, list, or write files one directory above the client's shared folder through RDPDR requests. This requires the victim to connect with drive redirection enabled. Version 3.25.0 patches the issue.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, a double-free vulnerability in kerberos_AcceptSecurityContext() and kerberos_InitializeSecurityContextA() (WinPR, winpr/libwinpr/sspi/Kerberos/kerberos.c) can cause a crash in any FreeRDP clients on systems where Kerberos and/or Kerberos U2U is configured (Samba AD member, or krb5 for NFS). The crash is triggered during NLA connection teardown and requires a failed authentication attempt. This issue has been patched in version 3.24.2.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, in persistent_cache_read_entry_v3() in libfreerdp/cache/persistent.c, persistent->bmpSize is updated before winpr_aligned_recalloc(). If realloc fails, bmpSize is inflated while bmpData points to the old buffer. This issue has been patched in version 3.24.2.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, in yuv_ensure_buffer() in libfreerdp/codec/h264.c, h264->width and h264->height are updated before the reallocation loop. If any winpr_aligned_recalloc() call fails, the function returns FALSE but width/height are already inflated. This issue has been patched in version 3.24.2.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, pixel data from adjacent heap memory is rendered to screen, potentially leaking sensitive data to the attacker. This issue has been patched in version 3.24.2.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, in resize_vbar_entry() in libfreerdp/codec/clear.c, vBarEntry->size is updated to vBarEntry->count before the winpr_aligned_recalloc() call. If realloc fails, size is inflated while pixels still points to the old, smaller buffer. On a subsequent call where count <= size (the inflated value), realloc is skipped. The caller then writes count * bpp bytes of attacker-controlled pixel data into the undersized buffer, causing a heap buffer overflow. This issue has been patched in version 3.24.2.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, progressive_decompress_tile_upgrade() detects a mismatch via progressive_rfx_quant_cmp_equal() but only emits WLog_WARN, execution continues. The wrapped value (247) is used as a shift exponent, causing undefined behavior and an approximately 80 billion iteration loop (CPU DoS). This issue has been patched in version 3.24.2.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, there is a heap-buffer-overflow READ vulnerability at 24 bytes before the allocation, in winpr_aligned_offset_recalloc(). This issue has been patched in version 3.24.2.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, an unvalidated auth_length field read from the network triggers a WINPR_ASSERT() failure in rts_read_auth_verifier_no_checks(), causing any FreeRDP client connecting through a malicious RDP Gateway to crash with SIGABRT. This is a pre-authentication denial of service affecting all FreeRDP clients using RPC-over-HTTP gateway transport. The assertion is active in default release builds (WITH_VERBOSE_WINPR_ASSERT=ON). This issue has been patched in version 3.24.2.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, a malicious RDP server can crash the FreeRDP client by sending audio data in IMA ADPCM format with an invalid initial step index value (>= 89). The unvalidated step index is read directly from the network and used to index into a 89-entry lookup table, triggering a WINPR_ASSERT() failure and process abort via SIGABRT. This affects any FreeRDP client that has audio redirection (RDPSND) enabled, which is the default configuration. This issue has been patched in version 3.24.2.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, there is an out-of-bounds read in freerdp_bitmap_decompress_planar when SrcSize is 0. The function dereferences *srcp (which points to pSrcData) without first verifying that SrcSize >= 1. When SrcSize is 0 and pSrcData is non-NULL, this reads one byte past the end of the source buffer. This vulnerability is fixed in 3.24.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, the gdi_surface_bits() function processes SURFACE_BITS_COMMAND messages sent by the RDP server. When the command is handled using NSCodec, the bmp.width and bmp.height values provided by the server are not properly validated against the actual desktop dimensions. A malicious RDP server can supply crafted bmp.width and bmp.height values that exceed the expected surface size. Because these values are used during bitmap decoding and memory operations without proper bounds checking, this can lead to a heap buffer overflow. Since the attacker can also control the associated pixel data transmitted by the server, the overflow may be exploitable to overwrite adjacent heap memory. This vulnerability is fixed in 3.24.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, there is an out-of-bounds read in MS-ADPCM and IMA-ADPCM decoders due to unchecked predictor and step_index values from input data. This vulnerability is fixed in 3.24.0.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, division by zero in MS-ADPCM and IMA-ADPCM decoders when nBlockAlign is 0, leading to a crash. In libfreerdp/codec/dsp.c, both ADPCM decoders use size % block_size where block_size = context->common.format.nBlockAlign. The nBlockAlign value comes from the Server Audio Formats PDU on the RDPSND channel. The value 0 is not validated anywhere before reaching the decoder. When nBlockAlign = 0, the modulo operation causes a SIGFPE (floating point exception) crash. This vulnerability is fixed in 3.24.0.