CVE-2026-91767 — MEDIUM (6.5)

Vulnerability 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.

CVSS Score

6.5

MEDIUM

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector

ADJACENT_NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

NONE

Availability

NONE

Related Weaknesses (CWE)

CWE-122

References

https://github.com/php/php-src/security/advisories/GHSA-xr7j-rvgx-xq5p

FAQ

What is CVE-2026-91767?

CVE-2026-91767 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 togeth...

How severe is CVE-2026-91767?

CVE-2026-91767 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-91767?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.