OpenSSL before 0.9.8y, 1.0.0 before 1.0.0k, and 1.0.1 before 1.0.1d does not properly perform signature verification for OCSP responses, which allows remote OCSP servers to cause a denial of service (NULL pointer dereference and application crash) via an invalid key.

OpenSSL 0.9.6 before 0.9.6d does not properly handle unknown message types, which allows remote attackers to cause a denial of service (infinite loop), as demonstrated using the Codenomicon TLS Test Tool.

The SSL/TLS handshaking code in OpenSSL 0.9.7a, 0.9.7b, and 0.9.7c, when using Kerberos ciphersuites, does not properly check the length of Kerberos tickets during a handshake, which allows remote attackers to cause a denial of service (crash) via a crafted SSL/TLS handshake that causes an out-of-bounds read.

The do_change_cipher_spec function in OpenSSL 0.9.6c to 0.9.6k, and 0.9.7a to 0.9.7c, allows remote attackers to cause a denial of service (crash) via a crafted SSL/TLS handshake that triggers a null dereference.

Integer overflow in OpenSSL 0.9.6 and 0.9.7 allows remote attackers to cause a denial of service (crash) via an SSL client certificate with certain ASN.1 tag values.

OpenSSL 0.9.6 and 0.9.7 does not properly track the number of characters in certain ASN.1 inputs, which allows remote attackers to cause a denial of service (crash) via an SSL client certificate that causes OpenSSL to read past the end of a buffer when the long form is used.

crypto/x509/x509_vfy.c in OpenSSL 1.0.2i allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) by triggering a CRL operation.

OpenSSL 0.9.6e uses assertions when detecting buffer overflow attacks instead of less severe mechanisms, which allows remote attackers to cause a denial of service (crash) via certain messages that cause OpenSSL to abort from a failed assertion, as demonstrated using SSLv2 CLIENT_MASTER_KEY messages, which are not properly handled in s2_srvr.c.

crypto/evp/e_aes_cbc_hmac_sha1.c in the AES-NI functionality in the TLS 1.1 and 1.2 implementations in OpenSSL 1.0.1 before 1.0.1d allows remote attackers to cause a denial of service (application crash) via crafted CBC data.

The ASN1 library in OpenSSL 0.9.6d and earlier, and 0.9.7-beta2 and earlier, allows remote attackers to cause a denial of service via invalid encodings.

Integer overflow in the EVP_EncodeUpdate function in crypto/evp/encode.c in OpenSSL before 1.0.1t and 1.0.2 before 1.0.2h allows remote attackers to cause a denial of service (heap memory corruption) via a large amount of binary data.

OpenSSL 0.9.8s and 1.0.0f does not properly support DTLS applications, which allows remote attackers to cause a denial of service (crash) via unspecified vectors related to an out-of-bounds read. NOTE: this vulnerability exists because of an incorrect fix for CVE-2011-4108.

The GOST ENGINE in OpenSSL before 1.0.0f does not properly handle invalid parameters for the GOST block cipher, which allows remote attackers to cause a denial of service (daemon crash) via crafted data from a TLS client.

ssl/s3_pkt.c in OpenSSL before 0.9.8i allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a DTLS ChangeCipherSpec packet that occurs before ClientHello.

A bug exists in the way mod_ssl handled client renegotiations. A remote attacker could send a carefully crafted request that would cause mod_ssl to enter a loop leading to a denial of service. This bug can be only triggered with Apache HTTP Server version 2.4.37 when using OpenSSL version 1.1.1 or later, due to an interaction in changes to handling of renegotiation attempts.

The BN_mod_sqrt() function, which computes a modular square root, contains a bug that can cause it to loop forever for non-prime moduli. Internally this function is used when parsing certificates that contain elliptic curve public keys in compressed form or explicit elliptic curve parameters with a base point encoded in compressed form. It is possible to trigger the infinite loop by crafting a certificate that has invalid explicit curve parameters. Since certificate parsing happens prior to verification of the certificate signature, any process that parses an externally supplied certificate may thus be subject to a denial of service attack. The infinite loop can also be reached when parsing crafted private keys as they can contain explicit elliptic curve parameters. Thus vulnerable situations include: - TLS clients consuming server certificates - TLS servers consuming client certificates - Hosting providers taking certificates or private keys from customers - Certificate authorities parsing certification requests from subscribers - Anything else which parses ASN.1 elliptic curve parameters Also any other applications that use the BN_mod_sqrt() where the attacker can control the parameter values are vulnerable to this DoS issue. In the OpenSSL 1.0.2 version the public key is not parsed during initial parsing of the certificate which makes it slightly harder to trigger the infinite loop. However any operation which requires the public key from the certificate will trigger the infinite loop. In particular the attacker can use a self-signed certificate to trigger the loop during verification of the certificate signature. This issue affects OpenSSL versions 1.0.2, 1.1.1 and 3.0. It was addressed in the releases of 1.1.1n and 3.0.2 on the 15th March 2022. Fixed in OpenSSL 3.0.2 (Affected 3.0.0,3.0.1). Fixed in OpenSSL 1.1.1n (Affected 1.1.1-1.1.1m). Fixed in OpenSSL 1.0.2zd (Affected 1.0.2-1.0.2zc).

During key agreement in a TLS handshake using a DH(E) based ciphersuite a malicious server can send a very large prime value to the client. This will cause the client to spend an unreasonably long period of time generating a key for this prime resulting in a hang until the client has finished. This could be exploited in a Denial Of Service attack. Fixed in OpenSSL 1.1.0i-dev (Affected 1.1.0-1.1.0h). Fixed in OpenSSL 1.0.2p-dev (Affected 1.0.2-1.0.2o).

Internally libssl in OpenSSL calls X509_verify_cert() on the client side to verify a certificate supplied by a server. That function may return a negative return value to indicate an internal error (for example out of memory). Such a negative return value is mishandled by OpenSSL and will cause an IO function (such as SSL_connect() or SSL_do_handshake()) to not indicate success and a subsequent call to SSL_get_error() to return the value SSL_ERROR_WANT_RETRY_VERIFY. This return value is only supposed to be returned by OpenSSL if the application has previously called SSL_CTX_set_cert_verify_callback(). Since most applications do not do this the SSL_ERROR_WANT_RETRY_VERIFY return value from SSL_get_error() will be totally unexpected and applications may not behave correctly as a result. The exact behaviour will depend on the application but it could result in crashes, infinite loops or other similar incorrect responses. This issue is made more serious in combination with a separate bug in OpenSSL 3.0 that will cause X509_verify_cert() to indicate an internal error when processing a certificate chain. This will occur where a certificate does not include the Subject Alternative Name extension but where a Certificate Authority has enforced name constraints. This issue can occur even with valid chains. By combining the two issues an attacker could induce incorrect, application dependent behaviour. Fixed in OpenSSL 3.0.1 (Affected 3.0.0).

If an SSL/TLS server or client is running on a 32-bit host, and a specific cipher is being used, then a truncated packet can cause that server or client to perform an out-of-bounds read, usually resulting in a crash. For OpenSSL 1.1.0, the crash can be triggered when using CHACHA20/POLY1305; users should upgrade to 1.1.0d. For Openssl 1.0.2, the crash can be triggered when using RC4-MD5; users who have not disabled that algorithm should update to 1.0.2k.

In OpenSSL 1.1.0 before 1.1.0d, if a malicious server supplies bad parameters for a DHE or ECDHE key exchange then this can result in the client attempting to dereference a NULL pointer leading to a client crash. This could be exploited in a Denial of Service attack.

The ephemeral ECDH ciphersuite functionality in OpenSSL 0.9.8 through 0.9.8r and 1.0.x before 1.0.0e does not ensure thread safety during processing of handshake messages from clients, which allows remote attackers to cause a denial of service (daemon crash) via out-of-order messages that violate the TLS protocol.

The kssl_keytab_is_available function in ssl/kssl.c in OpenSSL before 0.9.8n, when Kerberos is enabled but Kerberos configuration files cannot be opened, does not check a certain return value, which allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via SSL cipher negotiation, as demonstrated by a chroot installation of Dovecot or stunnel without Kerberos configuration files inside the chroot.

OpenSSL before 0.9.8m does not check for a NULL return value from bn_wexpand function calls in (1) crypto/bn/bn_div.c, (2) crypto/bn/bn_gf2m.c, (3) crypto/ec/ec2_smpl.c, and (4) engines/e_ubsec.c, which has unspecified impact and context-dependent attack vectors.

OpenSSL 0.9.8i and earlier does not properly check the return value from the EVP_VerifyFinal function, which allows remote attackers to bypass validation of the certificate chain via a malformed SSL/TLS signature for DSA and ECDSA keys.

The ssl3_get_client_key_exchange function in s3_srvr.c in OpenSSL 1.0.2 before 1.0.2a, when client authentication and an ephemeral Diffie-Hellman ciphersuite are enabled, allows remote attackers to cause a denial of service (daemon crash) via a ClientKeyExchange message with a length of zero.

Memory leak in the tls_decrypt_ticket function in t1_lib.c in OpenSSL before 0.9.8zc, 1.0.0 before 1.0.0o, and 1.0.1 before 1.0.1j allows remote attackers to cause a denial of service (memory consumption) via a crafted session ticket that triggers an integrity-check failure.

The ssl3_take_mac function in ssl/s3_both.c in OpenSSL 1.0.1 before 1.0.1f allows remote TLS servers to cause a denial of service (NULL pointer dereference and application crash) via a crafted Next Protocol Negotiation record in a TLS handshake.

Memory leak in d1_srtp.c in the DTLS SRTP extension in OpenSSL 1.0.1 before 1.0.1j allows remote attackers to cause a denial of service (memory consumption) via a crafted handshake message.

slapd (aka ns-slapd) in 389 Directory Server before 1.2.8.a2 does not properly manage the c_timelimit field of the connection table element, which allows remote attackers to cause a denial of service (daemon outage) via Simple Paged Results connections, as demonstrated by using multiple processes to replay TCP sessions, a different vulnerability than CVE-2011-0019.

Google Chrome before 9.0.597.84 does not properly handle a missing key in an extension, which allows remote attackers to cause a denial of service (application crash) via a crafted extension.

Pexip Infinity before 24.1 has Improper Input Validation, leading to temporary denial of service via SIP.

Google Chrome before 11.0.696.57 does not properly present file dialogs, which allows remote attackers to cause a denial of service or possibly have unspecified other impact via unknown vectors that lead to "dangling pointers."

Google Chrome before 10.0.648.127 on Linux does not properly handle parallel execution of calls to the print method, which might allow remote attackers to cause a denial of service (application crash) via crafted JavaScript code.

Google Chrome before 11.0.696.57 on Linux does not properly interact with the X Window System, which allows remote attackers to cause a denial of service (application crash) via unspecified vectors.

The server in Microsoft Active Directory on Windows Server 2003 SP2 does not properly handle an update request for a service principal name (SPN), which allows remote attackers to cause a denial of service (authentication downgrade or outage) via a crafted request that triggers name collisions, aka "Active Directory SPN Validation Vulnerability."

The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not validate a certain size value during memory allocation, which might allow remote attackers to cause a denial of service (daemon crash) via unspecified vectors, related to "underflow errors."

Cisco Wireless LAN Controller (WLC) Software 7.4 before 7.4.130.0(MD) and 7.5, 7.6, and 8.0 before 8.0.110.0(ED) allows remote attackers to cause a denial of service (device reload) via crafted Bonjour traffic, aka Bug ID CSCur66908.

The afs_linux_lock function in afs/LINUX/osi_vnodeops.c in the kernel module in OpenAFS 1.4.14, 1.4.12, 1.4.7, and possibly other versions does not properly handle errors, which allows attackers to cause a denial of service via unknown vectors. NOTE: some of these details are obtained from third party information.

Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not properly check the amount of compression in zlib-compressed data, which allows remote attackers to cause a denial of service via a large compression factor.

Weborf before 0.12.5 is affected by a Denial of Service (DOS) due to malformed fields in HTTP.

The Neighbor Discovery (ND) protocol implementation in the IPv6 stack in Cisco IOS XE 2.1 through 3.17S, IOS XR 2.0.0 through 5.3.2, and NX-OS allows remote attackers to cause a denial of service (packet-processing outage) via crafted ND messages, aka Bug ID CSCuz66542, as exploited in the wild in May 2016.

The do_standalone function in the MIT krb5 KDC database propagation daemon (kpropd) in Kerberos 1.7, 1.8, and 1.9, when running in standalone mode, does not properly handle when a worker child process "exits abnormally," which allows remote attackers to cause a denial of service (listening process termination, no new connections, and lack of updates in slave KVC) via unspecified vectors.

Dell iDRAC8 versions prior to 2.83.83.83 contain a denial of service vulnerability. A remote unauthenticated attacker could potentially exploit this vulnerability to cause resource exhaustion in the webserver, resulting in a denial of service condition.

STCAPP (aka the SCCP telephony control application) on Cisco IOS before 15.0(1)XA1 does not properly handle multiple calls to a shared line, which allows remote attackers to cause a denial of service (port hang) by simultaneously ending two calls that were controlled by CallManager Express (CME), aka Bug ID CSCtd42552.