CVE-2026-91768

Medium

Description

The IPv6 branch of the FastCGI client access check compares only the first 12 bytes of a 16-byte IPv6 address, so listen.allowed_clients matches on a /96 prefix instead of the exact address. An attacker who can source an address sharing the first 96 bits with an allowed one passes the check and reaches the FastCGI endpoint.

SeverityMedium

CVSS6.5

Exploit probability—

Product

Php

PublishedSep 25, 2026

First seenSep 25, 2026

Weakness typeCWE-1023CWE-1023

How to fix

Update

php php8.2.34, 8.3.35, 8.4.26, 8.5.11 or later

Vendor advisories

github.com/php/php-src/security/advisories/GHSA-62xp-839h-2637

Affected products

Product	Affected versions	Fixed in
php php	8.2.0 ≤ v < 8.2.34, 8.3.0 ≤ v < 8.3.35, 8.4.0 ≤ v < 8.4.26, 8.5.0 ≤ v < 8.5.11	8.2.34, 8.3.35, 8.4.26, 8.5.11

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.