CVE-2026-91767

CVE Details

Release Date:	2026-09-25
Impact:	Moderate	What is this?

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.

See more information about CVE-2026-91767 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	6.5
Vector String:	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Version:	3.1
Attack Vector:	Adjacent_Network
Attack Complexity:	Low
Privileges Required:	None
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	None
Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 8 (libzip)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pear)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-apcu)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-rrd)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-xdebug)	ELSA-2026-87080	2026-10-21
Oracle Linux version 8 (php-pecl-zip)	ELSA-2026-87080	2026-10-21