ssl/t1_lib.c in OpenSSL 0.9.8h through 0.9.8q and 1.0.0 through 1.0.0c allows remote attackers to cause a denial of service (crash), and possibly obtain sensitive information in applications that use OpenSSL, via a malformed ClientHello handshake message that triggers an out-of-bounds memory access, aka "OCSP stapling vulnerability."

Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the "signature_algorithms_cert" TLS extension. The crash occurs if an invalid or unrecognised signature algorithm is received from the peer. This could be exploited by a malicious peer in a Denial of Service attack. OpenSSL version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue. This issue did not affect OpenSSL versions prior to 1.1.1d. Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f).

Memory leak in the zlib_stateful_finish function in crypto/comp/c_zlib.c in OpenSSL 0.9.8l and earlier and 1.0.0 Beta through Beta 4 allows remote attackers to cause a denial of service (memory consumption) via vectors that trigger incorrect calls to the CRYPTO_cleanup_all_ex_data function, as demonstrated by use of SSLv3 and PHP with the Apache HTTP Server, a related issue to CVE-2008-1678.

Multiple integer overflows in OpenSSL 1.0.1 before 1.0.1s and 1.0.2 before 1.0.2g allow remote attackers to cause a denial of service (heap memory corruption or NULL pointer dereference) or possibly have unspecified other impact via a long digit string that is mishandled by the (1) BN_dec2bn or (2) BN_hex2bn function, related to crypto/bn/bn.h and crypto/bn/bn_print.c.

The dtls1_retrieve_buffered_fragment function in ssl/d1_both.c in OpenSSL before 1.0.0 Beta 2 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an out-of-sequence DTLS handshake message, related to a "fragment bug."

OpenSSL before 0.9.8k on WIN64 and certain other platforms does not properly handle a malformed ASN.1 structure, which allows remote attackers to cause a denial of service (invalid memory access and application crash) by placing this structure in the public key of a certificate, as demonstrated by an RSA public key.

The dtls1_buffer_record function in ssl/d1_pkt.c in OpenSSL 0.9.8k and earlier 0.9.8 versions allows remote attackers to cause a denial of service (memory consumption) via a large series of "future epoch" DTLS records that are buffered in a queue, aka "DTLS record buffer limitation bug."

Multiple memory leaks in the dtls1_process_out_of_seq_message function in ssl/d1_both.c in OpenSSL 0.9.8k and earlier 0.9.8 versions allow remote attackers to cause a denial of service (memory consumption) via DTLS records that (1) are duplicates or (2) have sequence numbers much greater than current sequence numbers, aka "DTLS fragment handling memory leak."

Use-after-free vulnerability in the dtls1_retrieve_buffered_fragment function in ssl/d1_both.c in OpenSSL 1.0.0 Beta 2 allows remote attackers to cause a denial of service (openssl s_client crash) and possibly have unspecified other impact via a DTLS packet, as demonstrated by a packet from a server that uses a crafted server certificate.

The ASN1_STRING_print_ex function in OpenSSL before 0.9.8k allows remote attackers to cause a denial of service (invalid memory access and application crash) via vectors that trigger printing of a (1) BMPString or (2) UniversalString with an invalid encoded length.

A denial of service flaw was found in OpenSSL 0.9.8, 1.0.1, 1.0.2 through 1.0.2h, and 1.1.0 in the way the TLS/SSL protocol defined processing of ALERT packets during a connection handshake. A remote attacker could use this flaw to make a TLS/SSL server consume an excessive amount of CPU and fail to accept connections from other clients.

The OPENSSL_LH_flush() function, which empties a hash table, contains a bug that breaks reuse of the memory occuppied by the removed hash table entries. This function is used when decoding certificates or keys. If a long lived process periodically decodes certificates or keys its memory usage will expand without bounds and the process might be terminated by the operating system causing a denial of service. Also traversing the empty hash table entries will take increasingly more time. Typically such long lived processes might be TLS clients or TLS servers configured to accept client certificate authentication. The function was added in the OpenSSL 3.0 version thus older releases are not affected by the issue. Fixed in OpenSSL 3.0.3 (Affected 3.0.0,3.0.1,3.0.2).

In OpenSSL 1.1.0 before 1.1.0c, TLS connections using *-CHACHA20-POLY1305 ciphersuites are susceptible to a DoS attack by corrupting larger payloads. This can result in an OpenSSL crash. This issue is not considered to be exploitable beyond a DoS.

In OpenSSL 1.1.0 before 1.1.0c, applications parsing invalid CMS structures can crash with a NULL pointer dereference. This is caused by a bug in the handling of the ASN.1 CHOICE type in OpenSSL 1.1.0 which can result in a NULL value being passed to the structure callback if an attempt is made to free certain invalid encodings. Only CHOICE structures using a callback which do not handle NULL value are affected.

The ssl3_read_bytes function in record/rec_layer_s3.c in OpenSSL 1.1.0 before 1.1.0a allows remote attackers to cause a denial of service (infinite loop) by triggering a zero-length record in an SSL_peek call.

The tls_decrypt_ticket function in ssl/t1_lib.c in OpenSSL before 1.1.0 does not consider the HMAC size during validation of the ticket length, which allows remote attackers to cause a denial of service via a ticket that is too short.

Memory leak in the zlib_stateful_init function in crypto/comp/c_zlib.c in libssl in OpenSSL 0.9.8f through 0.9.8h allows remote attackers to cause a denial of service (memory consumption) via multiple calls, as demonstrated by initial SSL client handshakes to the Apache HTTP Server mod_ssl that specify a compression algorithm.

Integer overflow in the EVP_EncryptUpdate function in crypto/evp/evp_enc.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 data.

The DTLS implementation in OpenSSL before 1.1.0 does not properly restrict the lifetime of queue entries associated with unused out-of-order messages, which allows remote attackers to cause a denial of service (memory consumption) by maintaining many crafted DTLS sessions simultaneously, related to d1_lib.c, statem_dtls.c, statem_lib.c, and statem_srvr.c.

The TS_OBJ_print_bio function in crypto/ts/ts_lib.c in the X.509 Public Key Infrastructure Time-Stamp Protocol (TSP) implementation in OpenSSL through 1.0.2h allows remote attackers to cause a denial of service (out-of-bounds read and application crash) via a crafted time-stamp file that is mishandled by the "openssl ts" command.

The ASN1_TFLG_COMBINE implementation in crypto/asn1/tasn_dec.c in OpenSSL before 0.9.8zh, 1.0.0 before 1.0.0t, 1.0.1 before 1.0.1q, and 1.0.2 before 1.0.2e mishandles errors caused by malformed X509_ATTRIBUTE data, which allows remote attackers to obtain sensitive information from process memory by triggering a decoding failure in a PKCS#7 or CMS application.

crypto/rsa/rsa_ameth.c in OpenSSL 1.0.1 before 1.0.1q and 1.0.2 before 1.0.2e allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via an RSA PSS ASN.1 signature that lacks a mask generation function parameter.

The PKCS7_dataDecodefunction in crypto/pkcs7/pk7_doit.c in OpenSSL before 0.9.8zg, 1.0.0 before 1.0.0s, 1.0.1 before 1.0.1n, and 1.0.2 before 1.0.2b allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a PKCS#7 blob that uses ASN.1 encoding and lacks inner EncryptedContent data.