---
cve: "CVE-2026-67693"
severity: "LOW"
cvss: 3.7
epss: "0.2%"
vendor: "n/a"
kev: false
exploited: false
published: "2026-10-08 00:00:00"
tags: [cve, security, low]
source: tsecurity.de CVE-Dossier
exported: "2026-10-22T20:03:30+02:00"
---

# CVE-2026-67693

> 3.7 LOW · 🧪 PoC

## Beschreibung

An issue in gnutls v.3.8.13 allows an attacker to obtain sensitive information via failing to reject end-entity X.509 certificates that contain a contradictory combination of Key Usage (KU) and Extended Key Usage (EKU)

## CNA-Record (Kanon, cvelistV5)

- CNA: **mitre**
- State: PUBLISHED
- Stand: 2026-10-19 15:04:22

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **no**
  - Technical Impact: **partial**

## CVSS-Vektor

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

| 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 | Gering | warn |
| I Integrität | Keine | good |
| A Verfügbarkeit | Keine | good |

## Schwachstellen-Klasse

- **CWE-367** — Time-of-check Time-of-use (TOCTOU) Race Condition
  The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

## Angriffsmuster (CAPEC)

- [CAPEC-27 — Leveraging Race Conditions via Symbolic Links](https://capec.mitre.org/data/definitions/27.html) _(Severity: High)_
- [CAPEC-29 — Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions](https://capec.mitre.org/data/definitions/29.html) _(Severity: High)_

## BSI-Hinweise (deutsch)

- [GnuTLS: Mehrere Schwachstellen](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-3843) — _BSI-Einstufung: hoch_
  Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in GnuTLS ausnutzen, um Sicherheitsvorkehrungen zu umgehen, Daten offenzulegen oder zu manipulieren oder einen Denial-of-Service-Zustand auszulösen.

## Referenzen

- <http://gnutls.com>
- <https://gitlab.com/gnutls/gnutls/-/blob/3.8.13/lib/x509/verify.c#L1119-1178>
- <https://gist.github.com/lkloliver/6fbfc191bc6163942c8017551ac3f238>
- <https://gitlab.com/gnutls/gnutls/-/work_items/1642>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-67693/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_