Wolfssl

wc_Blake2bHmacFinal and wc_Blake2sHmacFinal discard the message when the key length exceeds the block size, producing a MAC that is independent of the input. When the supplied key is longer than the BLAKE2 block size the key-hashing branch reinitialized the running hash state, discarding the accumulated message data, so the resulting MAC depended only on the key and not on the message being authenticated. This bug is specific to the HMAC-BLAKE2 APIs that were added in wolfSSL version 5.9.0.Show less

HMAC zero-length tag forgery in EVP_DigestVerifyFinal, where a zero-length tag could be accepted as valid during HMAC verification. In the OpenSSL-compatibility HMAC verify path the supplied signature length was only checked as not exceeding the MAC length, so a zero-length or otherwise truncated tag could pass verification. The fix requires the supplied tag length to exactly equal the MAC length and rejects a zero-length MAC, so a forged short or empty tag is no longer accepted.Show less

The ML-KEM ARM64 NEON ciphertext comparison only compares half of the input, breaking the Fujisaki-Okamoto transform's implicit rejection and weakening IND-CCA2 security on that code path. The constant-time comparison effectively ignored part of the re-encrypted ciphertext, so a decapsulating party could fail to detect a manipulated ciphertext and proceed without the standard's required implicit rejection.Show less

PKCS#12 MAC verification uses an attacker-controlled comparison length, weakening the integrity check on the MAC and allowing a mismatched MAC to be accepted. The PKCS#12 verify path compared the locally computed HMAC against the MAC parsed from the PKCS#12 structure using a length taken directly from the attacker-supplied input, without first verifying that it equals the length of the digest actually produced by the configured algorithm. A truncated or zero-length stored MAC could therefore be accepted, defeating the integrity protection of the MAC.Show less

TLS 1.3 post-handshake authentication (PHA) issue where a server could accept a client's Finished message without the client having sent a Certificate and CertificateVerify. The post-handshake-auth exemption that allows an empty/absent peer certificate was only intended for the initial handshake, but it was also being applied while a post-handshake CertificateRequest was still outstanding. The check is now scoped to the initial handshake only: on the server, once a post-handshake CertificateRequest has been sent (certReqCtx is set), a peer certificate and a valid CertificateVerify are required again before the Finished is accepted, with empty-certificate handling following the configured verify mode (FAIL_IF_NO_PEER_CERT) just as during first-handshake client authentication. Only affects TLS 1.3 servers built with post-handshake authentication support (WOLFSSL_POST_HANDSHAKE_AUTH / --enable-postauth, included in --enable-all) that enable WOLFSSL_VERIFY_POST_HANDSHAKE and request a client certificate after the handshake via wolfSSL_request_certificate(). Clients, and servers that do not use post-handshake authentication, are unaffected.Show less

Missing SNI/ALPN binding on stateful (session-ID) resumption, which previously skipped the binding check performed for ticket-based resumption. A cached session could be resumed under a different SNI/ALPN than originally negotiated and, where client-authentication policy differs across virtual hosts, carry the cached peer-authentication state into a context it was not established for. Resumption now verifies the SNI/ALPN binding for all paths and declines (falling back to a full handshake) on mismatch.Show less

OCSP CertID serial-number length-confusion in wolfSSL_OCSP_resp_find_status allows a same-issuer SingleResponse whose serial is a prefix of the target serial to be reported as the revocation status of a different certificate. The lookup compared serial-number bytes without first requiring the two serial numbers to be of equal length, so a SingleResponse for one certificate (same issuer) whose serial is a prefix of the target's serial would match, returning the wrong certificate's status. The fix requires the serial lengths to be equal before comparing the serial bytes.Show less

The PKCS#7 decode path ignores the caller-supplied output buffer size (outputSz), allowing decoded content to be written past the bounds of the provided buffer. This affects wolfSSL 5.9.0 and earlier and was fixed in the 5.9.1 release.Show less

A heap buffer overflow could occur in the DTLS 1.3 ACK serialization path before the connecting peer is authenticated. The buffer overflow was due to an integer truncation when computing the length of the ACK record-number list, causing an undersized buffer to be allocated and then overrun. This affects builds using DTLS 1.3 and wolfSSL version 5.9.0 and earlier. A fix was added to the 5.9.1 release.Show less

A CRL critical extension bypass exists in ParseCRL_Extensions where critical extensions are not properly enforced, allowing a crafted CRL with an unhandled critical extension to be accepted. This only affects builds with CRL support enabled and where a crafted CRL had a trusted signature when parsed.Show less

Use-after-free in PQC hybrid key-share handling. This is an incomplete-fix follow-up to CVE-2026-5460 (released in 5.9.1): a malicious TLS 1.3 server sending a truncated PQC hybrid KeyShare can still trigger the error cleanup path to operate on freed memory.Show less

Chain intermediate CA:TRUE without keyCertSign accepted as a signing CA. Intermediate CA certificates are required to have the keyCertSign key usage when a Key Usage extension is present, but chain-supplied temporary CAs (WOLFSSL_TEMP_CA) added while building a certificate path were previously exempted from this check, so an intermediate asserting CA:TRUE but lacking keyCertSign was accepted as a signing CA. The check now applies to chain-supplied temporary CAs as well; only operator-loaded root certificates (WOLFSSL_USER_CA) and self-signed roots remain exempt. Per RFC 5280 an absent Key Usage extension implies all usages, so the requirement is enforced only when the extension is actually present (extKeyUsageSet). Affects the OpenSSL-compatibility certificate-path-building path (X509_verify_cert / X509_STORE, OPENSSL_EXTRA/OPENSSL_ALL), where untrusted chain intermediates are added as temporary CAs; native (non-OpenSSL-compat) certificate verification does not create temporary CAs and is unaffected. Within those builds, the check applies unless ALLOW_INVALID_CERTSIGN is defined.Show less

Un-negotiated Raw Public Key (RFC 7250) accepted in place of an X.509 certificate, bypassing chain validation. A raw public key has no chain, so ParseCertRelative() accepts it without performing any trust verification; it must therefore only be accepted when RPK was actually negotiated for that peer. The check now defaults the expected type to X.509 (per RFC 7250/8446) when no type was negotiated, comparing against the received server certificate type on the client and the selected client certificate type on the server, and rejects any mismatch, including an un-negotiated raw public key, with UNSUPPORTED_CERTIFICATE. Only affects builds with Raw Public Key support (HAVE_RPK) enabled - disabled by default in a standalone build, but included in --enable-all.Show less