A vulnerability was found in OpenSSL 1.0.2. When an application encounters a fatal protocol error and then calls SSLshutdown() twice, OpenSSL can respond differently to the calling application if a 0 byte record is received with invalid padding compared to if a 0 byte record is received with an invalid MAC. This difference in behaviour can be detected by a remote peer, then this amounts to a padding oracle that could be used to decrypt data. In order for this to be exploitable "non-stitched" ciphersuites must be in use. Also the application must call SSLshutdown() twice even if a protocol error has occurred (applications should not do this but some do anyway). AEAD ciphersuites are not impacted. This issue does not impact OpenSSL 1.1.1 or 1.1.0.

Upstream bug: https://www.openssl.org/news/secadv/20190226.txt

Upstream Patch: https://github.com/openssl/openssl/commit/e9bbefbf0f24c57645e7ad6a5a71ae649d18ac8e

A flaw was found in openssl. A miscalculation of a buffer size was found in openssl's SM2 decryption function, allowing up to 62 arbitrary bytes to be written outside of the buffer. A remote attacker could use this flaw to crash an application supporting SM2 signature or encryption algorithm, or, possibly, execute arbitrary code with the permissions of the user running that application. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Apache Log4j is vulnerable to a man-in-the-middle attack, caused by improper certificate validation with host mismatch in the SMTP appender. An attacker could exploit this vulnerability to launch a man-in-the-middle attack and gain access to the communication channel between endpoints to obtain sensitive information or further compromise the system.

ASN.1 strings are represented internally within OpenSSL as an ASN1STRING structure which contains a buffer holding the string data and a field holding the buffer length. This contrasts with normal C strings which are repesented as a buffer for the string data which is terminated with a NUL (0) byte. Although not a strict requirement, ASN.1 strings that are parsed using OpenSSL's own "d2i" functions (and other similar parsing functions) as well as any string whose value has been set with the ASN1STRINGset() function will additionally NUL terminate the byte array in the ASN1STRING structure. However, it is possible for applications to directly construct valid ASN1STRING structures which do not NUL terminate the byte array by directly setting the "data" and "length" fields in the ASN1STRING array. This can also happen by using the ASN1STRINGset0() function. Numerous OpenSSL functions that print ASN.1 data have been found to assume that the ASN1STRING byte array will be NUL terminated, even though this is not guaranteed for strings that have been directly constructed. Where an application requests an ASN.1 structure to be printed, and where that ASN.1 structure contains ASN1STRINGs that have been directly constructed by the application without NUL terminating the "data" field, then a read buffer overrun can occur. The same thing can also occur during name constraints processing of certificates (for example if a certificate has been directly constructed by the application instead of loading it via the OpenSSL parsing functions, and the certificate contains non NUL terminated ASN1STRING structures). It can also occur in the X509get1email(), X509REQget1email() and X509get1ocsp() functions. If a malicious actor can cause an application to directly construct an ASN1STRING and then process it through one of the affected OpenSSL functions then this issue could be hit. This might result in a crash (causing a Denial of Service attack). It could also result in the disclosure of private memory contents (such as private keys, or sensitive plaintext). Fixed in OpenSSL 1.1.1j (Affected 1.1.1-1.1.1k). Fixed in OpenSSL 1.0.2za (Affected 1.0.2-1.0.2y).

OpenSSL could allow a remote attacker to bypass security restrictions, caused by a a missing check in the validation logic of X.509 certificate chains by the X509VFLAGX509STRICT flag. By using any valid certificate or certificate chain to sign a specially crafted certificate, an attacker could bypass the check that non-CA certificates must not be able to issue other certificates and override the default purpose.

An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client. If a TLSv1.2 renegotiation ClientHello omits the signaturealgorithms extension (where it was present in the initial ClientHello), but includes a signaturealgorithmscert extension then a NULL pointer dereference will result, leading to a crash and a denial of service attack. A server is only vulnerable if it has TLSv1.2 and renegotiation enabled (which is the default configuration). OpenSSL TLS clients are not impacted by this issue. All OpenSSL 1.1.1 versions are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. Fixed in OpenSSL 1.1.1k (Affected 1.1.1-1.1.1j).

A null pointer dereference flaw was found in openssl. A remote attacker, able to control the arguments of the GENERALNAMEcmp function, could cause the application, compiled with openssl to crash resulting in a denial of service. The highest threat from this vulnerability is to system availability.

A flaw was found in openssl. OpenSSL 1.0.2 supports SSLv2. If a client attempts to negotiate SSLv2 with a server that is configured to support both SSLv2 and more recent SSL and TLS versions then a check is made for a version rollback attack when unpadding an RSA signature. However since there is no support for the SSLv2 protocol in 1.1.1 this is considered a bug and not a security issue in that version. OpenSSL 1.0.2 is out of support and no longer receiving public updates. Premium support customers of OpenSSL 1.0.2 should upgrade to 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.0.2y (Affected 1.0.2s-1.0.2x).

Calls to EVPCipherUpdate, EVPEncryptUpdate and EVPDecryptUpdate may overflow the output length argument in some cases where the input length is close to the maximum permissable length for an integer on the platform. In such cases the return value from the function call will be 1 (indicating success), but the output length value will be negative. This could cause applications to behave incorrectly or crash. OpenSSL versions 1.1.1i and below are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1j. OpenSSL versions 1.0.2x and below are affected by this issue. However OpenSSL 1.0.2 is out of support and no longer receiving public updates. Premium support customers of OpenSSL 1.0.2 should upgrade to 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.1.1j (Affected 1.1.1-1.1.1i). Fixed in OpenSSL 1.0.2y (Affected 1.0.2-1.0.2x).

Last updated 24 July 2024

Last updated 18 August 2025

OpenSSL could provide weaker than expected security, caused by a carry propagation flaw in the MIPS32 and MIPS64 squaring procedure. An attacker could exploit this vulnerability to launch further attacks on the system

Server or client applications that call the SSLcheckchain() 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 "signaturealgorithmscert" 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).

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.