CVE-2026-91767

Heap-buffer-overflow in php_openssl_matches_wildcard_name on crafted server cert wildcard CN

Published Sep 25, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4819-1 php8.2 security update
Debian DSA Debian DSA DSA-6514-1 php8.4 security update
Ubuntu USN Ubuntu USN USN-8936-1 PHP vulnerabilities
History
Type Values Removed Values Added
First Time appeared Php
Php php
CPEs cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
Vendors & Products Php
Php php
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Php Group
Php Group php
Vendors & Products Php Group
Php Group php
Type Values Removed Values Added
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.
Title Heap-buffer-overflow in php_openssl_matches_wildcard_name on crafted server cert wildcard CN
Weaknesses CWE-122
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
php
Published
Updated
Sep 28, 2026, 1:31 PM
Reserved
Sep 15, 2026, 12:41 AM
Status
Analyzed
Published
Sep 25, 2026, 9:17 PM
Modified
Oct 27, 2026, 1:14 PM
Severity
Moderate
Public date
Sep 25, 2026, 8:53 PM