Search: CVE-2026-91767

A heap-based buffer overflow vulnerability exists in PHP's OpenSSL extension function php_openssl_matches_wildcard_name(). This occurs when a TLS server certificate presents a wildcard name whose literal characters are longer than the hostname being verified, causing an underflow in the length argument passed to memchr(). This can lead to reading memory beyond the allocated heap buffer. The vulnerability is reachable from any default PHP client stream since verify_peer_name is enabled by default.