JLSEC-2026-264 Issue summary: A type confusion vulnerability exists in the TimeStamp Response verification code...

Issue summary: A type confusion vulnerability exists in the TimeStamp Response verification code where an ASN1TYPE union member is accessed without first validating the type, causing an invalid or NULL pointer dereference when processing a malformed TimeStamp Response file. Impact summary: An...

JLSEC-2026-239 Issue summary: Processing some specially crafted ASN.1 object identifiers or data containing them...

Issue summary: Processing some specially crafted ASN.1 object identifiers or data containing them may be very slow. Impact summary: Applications that use OBJobj2txt directly, or use any of the OpenSSL subsystems OCSP, PKCS7/SMIME, CMS, CMP/CRMF or TS with no message size limit may experience...

JLSEC-2026-259 Issue summary: Use of -addreject option with the openssl x509 application adds a trusted use instead...

Issue summary: Use of -addreject option with the openssl x509 application adds a trusted use instead of a rejected use for a certificate. Impact summary: If a user intends to make a trusted certificate rejected for a particular use it will be instead marked as trusted for that use. A copy & paste...

JLSEC-2026-219 Null pointer deference in openssl-src

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 i...

JLSEC-2026-220 The X.509 GeneralName type is a generic type for representing different types of names

The X.509 GeneralName type is a generic type for representing different types of names. One of those name types is known as EDIPartyName. OpenSSL provides a function GENERALNAMEcmp which compares different instances of a GENERALNAME to see if they are equal or not. This function behaves incorrect...

JLSEC-2026-236 Applications that use a non-default option when verifying certificates may be vulnerable to an...

Applications that use a non-default option when verifying certificates may be vulnerable to an attack from a malicious CA to circumvent certain checks. Invalid certificate policies in leaf certificates are silently ignored by OpenSSL and other certificate policy checks are skipped for that...

JLSEC-2026-246 Issue summary: Checking excessively long invalid RSA public keys may take a long time.

Issue summary: Checking excessively long invalid RSA public keys may take a long time. Impact summary: Applications that use the function EVPPKEYpubliccheck to check RSA public keys may experience long delays. Where the key that is being checked has been obtained from an untrusted source this may...

JLSEC-2026-223 openssl-src NULL pointer Dereference in `signature_algorithms` processing

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 NU...

JLSEC-2026-231 openssl-src subject to Timing Oracle in RSA Decryption

A timing based side channel exists in the OpenSSL RSA Decryption implementation which could be sufficient to recover a plaintext across a network in a Bleichenbacher style attack. To achieve a successful decryption an attacker would have to be able to send a very large number of trial messages fo...

JLSEC-2026-256 Issue summary: Parsing CMS AuthEnvelopedData message with maliciously crafted AEAD parameters can...

Issue summary: Parsing CMS AuthEnvelopedData or EnvelopedData message with maliciously crafted AEAD parameters can trigger a stack buffer overflow. Impact summary: A stack buffer overflow may lead to a crash, causing Denial of Service, or potentially remote code execution. When parsing CMS...

JLSEC-2026-225 Read buffer overruns processing ASN.1 strings

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...

JLSEC-2026-230 AES OCB fails to encrypt some bytes

AES OCB mode for 32-bit x86 platforms using the AES-NI assembly optimised implementation will not encrypt the entirety of the data under some circumstances. This could reveal sixteen bytes of data that was preexisting in the memory that wasn't written. In the special case of "in place" encryption...

JLSEC-2026-216 There is an overflow bug in the `x64_64` Montgomery squaring procedure used in exponentiation with...

There is an overflow bug in the x6464 Montgomery squaring procedure used in exponentiation with 512-bit moduli. No EC algorithms are affected. Analysis suggests that attacks against 2-prime RSA1024, 3-prime RSA1536, and DSA1024 as a result of this defect would be very difficult to perform and are...

JLSEC-2026-227 openssl-src's infinite loop in `BN_mod_sqrt()` reachable when parsing certificates

The BNmodsqrt 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...

JLSEC-2026-234 Vulnerable OpenSSL included in cryptography wheels

There is a type confusion vulnerability relating to X.400 address processing inside an X.509 GeneralName. X.400 addresses were parsed as an ASN1STRING but the public structure definition for GENERALNAME incorrectly specified the type of the x400Address field as ASN1TYPE. This field is subsequentl...

JLSEC-2026-221 Integer Overflow in openssl-src

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 succes...

JLSEC-2026-242 Issue summary: The POLY1305 MAC (message authentication code) implementation contains a bug that...

Issue summary: The POLY1305 MAC message authentication code implementation contains a bug that might corrupt the internal state of applications on the Windows 64 platform when running on newer X8664 processors supporting the AVX512-IFMA instructions. Impact summary: If in an application that uses...

JLSEC-2026-261 Issue summary: Writing large, newline-free data into a BIO chain using the line-buffering filter...

Issue summary: Writing large, newline-free data into a BIO chain using the line-buffering filter where the next BIO performs short writes can trigger a heap-based out-of-bounds write. Impact summary: This out-of-bounds write can cause memory corruption which typically results in a crash, leading ...

JLSEC-2026-263 Issue summary: Calling `PKCS12_get_friendlyname()` function on a maliciously crafted PKCS#12 file...

Issue summary: Calling PKCS12getfriendlyname function on a maliciously crafted PKCS12 file with a BMPString UTF-16BE friendly name containing non-ASCII BMP code point can trigger a one byte write before the allocated buffer. Impact summary: The out-of-bounds write can cause a memory corruption...

JLSEC-2026-233 openssl-src vulnerable to Use-after-free following `BIO_new_NDEF`

The public API function BIOnewNDEF is a helper function used for streaming ASN.1 data via a BIO. It is primarily used internally to OpenSSL to support the SMIME, CMS and PKCS7 streaming capabilities, but may also be called directly by end user applications. The function receives a BIO from the...