CVE-2026-91769
published 2026-09-25CVE-2026-91769: PHP's OpenSSL stream peer verification checks the certificate's subjectAltName entries first and, whenever no entry matches, falls back to the Common Name. RFC…
PriorityP418medium4.3CVSS 3.1
AVAACLPRNUINSUCLINAN
EPSS
0.16%
5.0th percentile
PHP's OpenSSL stream peer verification checks the certificate's subjectAltName entries first and, whenever no entry matches, falls back to the Common Name. RFC 6125 requires the CN to be ignored once the certificate presents any service identity, so a certificate carrying a non-matching DNS SAN was still accepted when its CN matched the requested peer_name. A certificate trusted by the client for one name can therefore be used to impersonate another.
Affected
21 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | php8.4 | — | — |
| php | php | — | — |
| php | php | >= 8.2.0 < 8.2.34 | 8.2.34 |
| php | php | >= 8.3.0 < 8.3.35 | 8.3.35 |
| php | php | >= 8.4.0 < 8.4.26 | 8.4.26 |
| php | php | >= 8.5.0 < 8.5.11 | 8.5.11 |
| php_7.4 | php | — | — |
| php_8.2 | php | — | — |
| php_8.3 | php | — | — |
| php_8.4 | php | — | — |
| php_group | php | >= 8.2.* < 8.2.34 | 8.2.34 |
| php_group | php | >= 8.3.* < 8.3.35 | 8.3.35 |
| php_group | php | >= 8.4.* < 8.4.26 | 8.4.26 |
| php_group | php | >= 8.5.* < 8.5.11 | 8.5.11 |
| ubuntu | php5 | — | — |
| ubuntu | php7.0 | — | — |
| ubuntu | php7.2 | — | — |
| ubuntu | php7.4 | — | — |
| ubuntu | php8.1 | — | — |
| ubuntu | php8.3 | — | — |
| ubuntu | php8.5 | — | — |
CVSS provenance
nvdv3.14.3MEDIUMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
vendor_redhat4.3MEDIUM
vendor_ubuntu3.4LOW
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VulDB
PHP up to 8.2.33/8.3.34/8.4.25/8.5.10 OpenSSL Stream certificate validation
vuldb·2026-09-25·CVSS 4.3
CVE-2026-91769 [MEDIUM] PHP up to 8.2.33/8.3.34/8.4.25/8.5.10 OpenSSL Stream certificate validation
A vulnerability was found in PHP up to 8.2.33/8.3.34/8.4.25/8.5.10 and classified as problematic. Impacted is an unknown function of the component OpenSSL Stream. Executing a manipulation can lead to improper certificate validation.
This vulnerability is registered as CVE-2026-91769. It is possible to launch the attack remotely. No exploit is available.
It is suggested to upgrade the affected component.
Ubuntu
PHP vulnerabilities
vendor_ubuntu·2026-10-19·CVSS 3.4
CVE-2026-93682 [LOW] PHP vulnerabilities
Title: PHP vulnerabilities
Summary: Several security issues were fixed in PHP.
It was discovered that PHP did not properly validate the size of MySQL
server packets in the mysqlnd driver. A malicious server could possibly use
this issue to cause PHP to crash, resulting in a denial of service. This
issue was only addressed in Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu
24.04 LTS, Ubuntu 26.04 LTS, and Ubuntu 26.10. (CVE-2025-1218)
It was discovered that PHP incorrectly handled response buffer sizes in the
SOAP HTTP client. A malicious server could possibly use this issue to cause
PHP to crash, resulting in a denial of service, or execute arbitrary code.
(CVE-2025-14181)
It was discovered that PHP incorrectly handled certain TAR archive headers
in the Phar extension. An attacker could pos
Red Hat
php: php: Server impersonation via Common Name fallback in TLS verification
vendor_redhat·2026-09-25·CVSS 4.3
CVE-2026-91769 [MEDIUM] CWE-295 php: php: Server impersonation via Common Name fallback in TLS verification
php: php: Server impersonation via Common Name fallback in TLS verification
PHP's OpenSSL stream peer verification checks the certificate's subjectAltName entries first and, whenever no entry matches, falls back to the Common Name. RFC 6125 requires the CN to be ignored once the certificate presents any service identity, so a certificate carrying a non-matching DNS SAN was still accepted when its CN matched the requested peer_name. A certificate trusted by the client for one name can therefore be used to impersonate another.
A flaw was found in PHP. This vulnerability allows server impersonation and potential information disclosure during Transport Layer Security (TLS) connections. When verifying peer certificates, PHP improperly falls back to matching the Common Name (CN) if no Subject
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-91769 php: php: Server impersonation via Common Name fallback in TLS verification [fedora-all]
bugzilla·2026-09-30·CVSS 4.3
CVE-2026-91769 [MEDIUM] CVE-2026-91769 php: php: Server impersonation via Common Name fallback in TLS verification [fedora-all]
CVE-2026-91769 php: php: Server impersonation via Common Name fallback in TLS verification [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
PHP's OpenSSL stream peer verification checks the certificate's subjectAltName entries first and, whenever no entry matches, falls back to the Common Name. RFC 6125 requires the CN to be ignored once the certificate presents any service identity, so a certificate carrying a non-matching DNS SAN was still accepted when its CN matched the requested peer_name. A certificate trusted by the client for one name can therefore be used to impersonate another.
Bugzilla
CVE-2026-91769 php: php: Server impersonation via Common Name fallback in TLS verification
bugzilla·2026-09-28·CVSS 4.3
CVE-2026-91769 [MEDIUM] CVE-2026-91769 php: php: Server impersonation via Common Name fallback in TLS verification
CVE-2026-91769 php: php: Server impersonation via Common Name fallback in TLS verification
PHP's OpenSSL stream peer verification checks the certificate's subjectAltName entries first and, whenever no entry matches, falls back to the Common Name. RFC 6125 requires the CN to be ignored once the certificate presents any service identity, so a certificate carrying a non-matching DNS SAN was still accepted when its CN matched the requested peer_name. A certificate trusted by the client for one name can therefore be used to impersonate another.
2026-09-25
Published