---
cve: "CVE-2026-40355"
severity: "MEDIUM"
cvss: 5.9
epss: "61%"
vendor: "MIT"
kev: false
exploited: false
published: "2026-04-28 06:16:03"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-18T01:57:07+02:00"
---

# CVE-2026-40355

> 5.9 MEDIUM · 🧪 PoC

## Beschreibung

In MIT Kerberos 5 (aka krb5) before 1.22.3, there is a NULL pointer dereference if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, causing the process to terminate in parse_nego_message.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 2e75f0d9362fb979f5fc92829431a590a130929f (Commit)

## Referenzen

- <https://web.mit.edu/kerberos/advisories/>
- <https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html>
- <https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f>
- <https://cert-portal.siemens.com/productcert/html/ssa-019113.html>
- <https://cert-portal.siemens.com/productcert/html/ssa-082556.html>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-40355) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_