---
cve: "CVE-2026-102266"
severity: "HIGH"
cvss: 7.4
epss: "0.2%"
vendor: "jpadilla"
kev: false
exploited: false
published: "2026-09-28 21:17:14"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-10-03T01:34:15+02:00"
---

# CVE-2026-102266

> 7.4 HIGH · 🧪 PoC

## Beschreibung

PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded key without applying prepare_key validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As a result, an attacker signs an HMAC token with the same zero-length key accepted by PyJWT. Consequently, forged token can carry arbitrary authenticated claims. This issue is fixed in version 2.14.0.

## CNA-Record (Kanon, cvelistV5)

- CNA: **GitHub_M**
- State: PUBLISHED
- Stand: 2026-09-29 19:35:42
- CNA-CVSS: **7.4** (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **poc**
  - Automatable: **no**
  - Technical Impact: **total**

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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 | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- f91ed44dd65baaf457f4b3353ed35e98a753934c (Commit)
- c6fe464b356ff4b1ebc9ba62172d331a40aa27df (Commit)

## Referenzen

- <https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r>
- <https://github.com/jpadilla/pyjwt/commit/f91ed44dd65baaf457f4b3353ed35e98a753934c>
- <https://github.com/jpadilla/pyjwt/releases/tag/2.14.0>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-102266) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_