---
cve: "CVE-2026-91768"
severity: "MEDIUM"
cvss: 6.5
epss: "0.6%"
vendor: "PHP Group"
kev: false
exploited: false
published: "2026-09-25 22:18:49"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-28T05:53:10+02:00"
---

# CVE-2026-91768

> 6.5 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Benachbart | warn |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Keine | good |
| A Verfügbarkeit | Keine | good |

## Referenzen

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

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-91768) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_