IPv6 ACL bypass in FastCGI listen.allowed_clients due to partial address comparison (memcmp 12 bytes) (PHP Group PHP)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.38 % · percentile 32 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- php
- NVD status
- Analyzed
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.
Weaknesses (CWE)
- CWE-1023 — Incomplete Comparison with Missing Factors
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | php |
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N | NVD · security@php.net (Secondary) |
European references
- ENISA EUVD · EUVD-2026-87350
- GCVE · GCVE-0-2026-91768
CERT-FR advisories
- CERTFR-2026-AVI-1227 — Multiples vulnérabilités dans PHP · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:php:php:*:*:*:*:*:*:*:*≥ 8.2.0 < 8.2.34cpe:2.3:a:php:php:*:*:*:*:*:*:*:*≥ 8.3.0 < 8.3.35cpe:2.3:a:php:php:*:*:*:*:*:*:*:*≥ 8.4.0 < 8.4.26cpe:2.3:a:php:php:*:*:*:*:*:*:*:*≥ 8.5.0 < 8.5.11
Affected products
| Product | Versions |
|---|---|
| PHP Group · PHP | affected 8.2.* < 8.2.34 ; affected 8.3.* < 8.3.35 ; affected 8.4.* < 8.4.26 ; affected 8.5.* < 8.5.11 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |