JLSEC-2026-252 Issue summary: Calling the OpenSSL API function `SSL_select_next_proto` with an empty supported...

Issue summary: Calling the OpenSSL API function SSLselectnextproto with an empty supported client protocols buffer may cause a crash or memory contents to be sent to the peer. Impact summary: A buffer overread can have a range of potential consequences such as unexpected application beahviour or ...

JLSEC-2026-247 Null pointer dereference in PKCS12 parsing

Issue summary: Processing a maliciously formatted PKCS12 file may lead OpenSSL to crash leading to a potential Denial of Service attack Impact summary: Applications loading files in the PKCS12 format from untrusted sources might terminate abruptly. A file in PKCS12 format can contain certificates...

JLSEC-2026-224 SM2 Decryption Buffer Overflow

In order to decrypt SM2 encrypted data an application is expected to call the API function EVPPKEYdecrypt. Typically an application will call this function twice. The first time, on entry, the "out" parameter can be NULL and, on exit, the "outlen" parameter is populated with the buffer size...

JLSEC-2026-265 Issue summary: Processing a malformed PKCS#12 file can trigger a NULL pointer dereference in the...

Issue summary: Processing a malformed PKCS12 file can trigger a NULL pointer dereference in the PKCS12itemdecryptd2iex function. Impact summary: A NULL pointer dereference can trigger a crash which leads to Denial of Service for an application processing PKCS12 files. The PKCS12itemdecryptd2iex...

JLSEC-2026-232 openssl-src contains Double free after calling `PEM_read_bio_ex`

The function PEMreadbioex reads a PEM file from a BIO and parses and decodes the "name" e.g. "CERTIFICATE", any header data and the payload data. If the function succeeds then the "nameout", "header" and "data" arguments are populated with pointers to buffers containing the relevant decoded data...

JLSEC-2026-215 OpenSSL 1.1.1 introduced a rewritten random number generator (RNG)

OpenSSL 1.1.1 introduced a rewritten random number generator RNG. This was intended to include protection in the event of a fork system call in order to ensure that the parent and child processes did not share the same RNG state. However this protection was not being used in the default case. A...

JLSEC-2026-277 Issue summary: Applications using RSASVE key encapsulation to establish a secret encryption key can...

Issue summary: Applications using RSASVE key encapsulation to establish a secret encryption key can send contents of an uninitialized memory buffer to a malicious peer. Impact summary: The uninitialized buffer might contain sensitive data from the previous execution of the application process whi...

JLSEC-2026-245 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 running on PowerPC CPU based platforms if the CPU provides vector instructions. Impact summary: If an attacker can influence whether the POLY1305 MAC...

JLSEC-2026-217 OpenSSL has internal defaults for a directory tree where it can find a configuration file as well as...

OpenSSL has internal defaults for a directory tree where it can find a configuration file as well as certificates used for verification in TLS. This directory is most commonly referred to as OPENSSLDIR, and is configurable with the --prefix / --openssldir configuration options. For OpenSSL versio...

JLSEC-2026-244 Issue summary: Generating excessively long X9.42 DH keys or checking excessively long X9.42 DH keys...

Issue summary: Generating excessively long X9.42 DH keys or checking excessively long X9.42 DH keys or parameters may be very slow. Impact summary: Applications that use the functions DHgeneratekey to generate an X9.42 DH key may experience long delays. Likewise, applications that use...

JLSEC-2026-258 Issue summary: The 'openssl dgst' command-line tool silently truncates input data to 16MB when using...

Issue summary: The 'openssl dgst' command-line tool silently truncates input data to 16MB when using one-shot signing algorithms and reports success instead of an error. Impact summary: A user signing or verifying files larger than 16MB with one-shot algorithms such as Ed25519, Ed448, or ML-DSA m...

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-2026-235 A security vulnerability has been identified in all supported versions

A security vulnerability has been identified in all supported versions of OpenSSL related to the verification of X.509 certificate chains that include policy constraints. Attackers may be able to exploit this vulnerability by creating a malicious certificate chain that triggers exponential use of...

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-2026-259 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-2026-239 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-2026-223 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-2026-264 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-2026-256 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-2026-246 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...