---
cve: "CVE-2026-5430"
severity: "CRITICAL"
cvss: 10.0
epss: "22.4%"
vendor: "WSO2"
kev: true
exploited: true
published: "2026-08-06 08:16:33"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-11-09T11:25:04+01:00"
---

# CVE-2026-5430

> 10.0 CRITICAL · ⚠️ CISA KEV (46 Tage) · 🔓 Exploited

## Beschreibung

The JWT authentication mechanism accepts tokens signed with algorithms other than those explicitly configured or supported. This allows an attacker to craft a JWT with an unsupported algorithm, which is then incorrectly validated, leading to unauthorized access.

Successful exploitation of this vulnerability may result in unauthorized access to the system, including the potential compromise of administrative accounts and full account takeover. The CVSS score is adjusted to 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) in single-tenant deployments, reflecting that the impact is contained within a single security authority boundary.

## CNA-Record (Kanon, cvelistV5)

- CNA: **WSO2**
- State: PUBLISHED
- Stand: 2026-09-25 03:55:16
- CNA-CVSS: **10.0** (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA KEV seit: **24.09.2026**
- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **active**
  - Automatable: **yes**
  - Technical Impact: **total**

## CVSS-Vektor

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

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

## Schwachstellen-Klasse

- **CWE-347** — Improper Verification of Cryptographic Signature
  The product does not verify, or incorrectly verifies, the cryptographic signature for data.

## Angriffsmuster (CAPEC)

- [CAPEC-463 — Padding Oracle Crypto Attack](https://capec.mitre.org/data/definitions/463.html) _(Severity: High)_
- [CAPEC-475 — Signature Spoofing by Improper Validation](https://capec.mitre.org/data/definitions/475.html) _(Severity: High)_

## BSI-Hinweise (deutsch)

- [WSO2 API Manager: Mehrere Schwachstellen](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-2085) — _BSI-Einstufung: kritisch_
  Ein Angreifer kann mehrere Schwachstellen in WSO2 API Manager ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um einen Denial of Service Angriff durchzuführen, um seine Privilegien zu erhöhen, um beliebigen Programmcode auszuführen, um einen SQL-Injection Angriff durchzuführen, um einen Cross-Site Scripting Angriff durchzuführen, um Informationen offenzulegen, und um Daten zu manipulieren.

## Referenzen

- <https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5328/>
- <https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-5430>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-5430/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_