---
cve: "CVE-2026-104056"
severity: "CRITICAL"
cvss: 9.8
epss: "0.2%"
vendor: "authlib"
kev: false
exploited: false
published: "2026-10-01 19:17:19"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-10-26T02:57:18+01:00"
---

# CVE-2026-104056

> 9.8 CRITICAL

## Beschreibung

Authlib version 1.7.2 and below contains a vulnerability where discovery JSON metadata is cached without validation or issuer-origin binding. This allows a poisoned discovery response to replace all endpoint values with attacker-controlled values rather than endpoint URLs that share the origin of the configured server metadata URL.

## CNA-Record (Kanon, cvelistV5)

- CNA: **certcc**
- State: PUBLISHED
- Stand: 2026-10-05 18:21:14

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **poc**
  - Automatable: **yes**
  - Technical Impact: **total**

## CVSS-Vektor

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

## Schwachstellen-Klasse

- **CWE-345** — Insufficient Verification of Data Authenticity
  The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
- **CWE-346** — Origin Validation Error
  The product does not properly verify that the source of data or communication is valid.
- **CWE-829** — Inclusion of Functionality from Untrusted Control Sphere
  The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.

## Angriffsmuster (CAPEC)

- [CAPEC-111 — JSON Hijacking (aka JavaScript Hijacking)](https://capec.mitre.org/data/definitions/111.html) _(Severity: High)_
- [CAPEC-141 — Cache Poisoning](https://capec.mitre.org/data/definitions/141.html) _(Severity: High)_
- [CAPEC-142 — DNS Cache Poisoning](https://capec.mitre.org/data/definitions/142.html) _(Severity: High)_
- [CAPEC-148 — Content Spoofing](https://capec.mitre.org/data/definitions/148.html) _(Severity: Medium)_
- [CAPEC-218 — Spoofing of UDDI/ebXML Messages](https://capec.mitre.org/data/definitions/218.html) _(Severity: Medium)_
- [CAPEC-384 — Application API Message Manipulation via Man-in-the-Middle](https://capec.mitre.org/data/definitions/384.html) _(Severity: Low)_
- [CAPEC-385 — Transaction or Event Tampering via Application API Manipulation](https://capec.mitre.org/data/definitions/385.html) _(Severity: Medium)_
- [CAPEC-386 — Application API Navigation Remapping](https://capec.mitre.org/data/definitions/386.html) _(Severity: Medium)_

## ATT&CK-Techniken

- [T1557.002 — Adversary-in-the-Middle: ARP Cache Poisoning](https://attack.mitre.org/techniques/T1557/002/)
- [T1584.002 — Compromise Infrastructure: DNS Server](https://attack.mitre.org/techniques/T1584/002/)
- [T1491 — Defacement](https://attack.mitre.org/techniques/T1491/)

## Referenzen

- <https://uziii2208.github.io/post/cve-2026-104056/>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-104056/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_