What’s Vulnerable › Vulnerabilities
CVE-2026-91767: Heap-buffer-overflow in php_openssl_matches_wildcard_name on crafted server cert wildcard CN
- Severity: medium (CVSS 6.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.1% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-09-25 · updated 2026-10-27
- Weakness: CWE-122
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.
Affected products
- PHP: from 8.2.0 before 8.2.34; from 8.3.0 before 8.3.35; from 8.4.0 before 8.4.26; from 8.5.0 before 8.5.11 — fixed in 8.2.34, 8.3.35, 8.4.26, 8.5.11
- PHP: from 8.2.* before 8.2.34; from 8.3.* before 8.3.35; from 8.4.* before 8.4.26; from 8.5.* before 8.5.11 — fixed in 8.2.34, 8.3.35, 8.4.26, 8.5.11
How to fix
Upgrade to a fixed version: PHP 8.2.34, 8.3.35, 8.4.26, 8.5.11; PHP 8.2.34, 8.3.35, 8.4.26, 8.5.11. Check the vendor advisory for mitigations.
References
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