CVE-2026-91767
php_openssl_matches_wildcard_name() in ext/openssl/xp_ssl.c underflows the length argument passed…
- Risk score
- 50/100
- CVSS
- 6.5 v3.1
- Exploit chance (30 days)
- 0.2%
- Published
- 25 Sep 2026
Open in the live forecast Today's forecast
What to know
- What it is
- php_openssl_matches_wildcard_name() in ext/openssl/xp_ssl.c underflows the length argument passed to memchr() when a TLS server certificate presents a wildcard name whose literal characters are together longer than the hostname being verified. A malicious server presenting such a certificate makes the PHP client read …
- Affected
- See advisory
- Fix
- Apply the vendor's security update; see the linked advisory.
- Exploitation
- No known exploitation
Why it is Yellow
- CVSS 6.5 medium
- On your watchlist: php, openssl
References
Original description
php_openssl_matches_wildcard_name() in ext/openssl/xp_ssl.c underflows the length argument passed to memchr() when a TLS server certificate presents a wildcard name whose literal characters are together longer than the hostname being verified. A malicious server presenting such a certificate makes the PHP client read up to SIZE_MAX bytes past the end of a heap allocation. The path is reachable from any default client stream, because verify_peer_name is enabled by default.
Last activity 25 Sep 2026. Patch Forecast updates every hour.