MEDIUM 6.5 NVD

CVE-2026-91768

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

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.

Remediation

$ sudo apt install --only-upgrade php8.4

References

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

Published: 2026-09-25 · Source: NVD · Feed updated: 2026-09-25

This medium severity vulnerability with a CVSS score of 6.5 was published on 2026-09-25 via NVD. A remediation command is available below.

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