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CVE-2026-91767GHSA-xr7j-rvgx-xq5p

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

PHP Group PHPRuntimes & languages
Open in ThreatlineRecord JSON
CVSS
6.5Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.15%Chance of exploitation activity in the next 30 days, higher than 4% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in8.2.34Also 8.3.35, 8.4.26 and 1 moreCVE List
Published25 Sep 2026Updated 28 Sep 2026CVE List

What fixes it

Show all 8 fixed versions

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 8

  • PHPaffected: 8.2.* before 8.2.34CVE List
  • PHPaffected: 8.3.* before 8.3.35CVE List
  • PHPaffected: 8.4.* before 8.4.26CVE List
  • PHPaffected: 8.5.* before 8.5.11CVE List
  • ext-openssl, php<8.2.34GitHub
  • ext-openssl, php<8.3.35GitHub
  • ext-openssl, php<8.4.26GitHub
  • ext-openssl, php<8.5.11GitHub

References 1