This page tracks the Debian fix status. The vulnerability itself is described on the main CVE page. View CVE-2026-91768 →

DEBIAN-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...

Original description

The description as published by the source.

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.

Source: OSV.dev (Open Source Vulnerabilities) OSV

Affected packages

Debian:12 php8.2

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.2.34-1~deb12u1"}]}]

Debian:13 php8.4

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.4.26-1~deb13u1"}]}]

Debian:14 php8.4

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.4.26-1"}]}]

References

advisory security-tracker.debian.org