---
cve: "CVE-2026-103259"
severity: "HIGH"
cvss: 8.5
epss: "0.2%"
vendor: "n8n-io"
kev: false
exploited: false
published: "2026-10-01 11:17:20"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-10-05T11:32:46+02:00"
---

# CVE-2026-103259

> 8.5 HIGH · 🧪 PoC

## Beschreibung

n8n versions before 2.39.6 and 2.40.0 before 2.40.1 contain a session token leakage vulnerability in the Dynamic Credentials authorize and revoke endpoints. Attackers with resolver registration capability can capture collaborators' session tokens by setting a fallback resolver to an attacker-controlled endpoint during the account connection flow, enabling unauthorized credential access.

## CNA-Record (Kanon, cvelistV5)

- CNA: **VulnCheck**
- State: PUBLISHED
- Stand: 2026-10-01 19:27:17
- CNA-CVSS: **8.5** (`CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:A/VC:H/VI:H/VA:H/SC:H/SI:L/SA:N`)

## CISA-Anreicherung (vulnrichment/ADP)

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

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:A/VC:H/VI:H/VA:H/SC:H/SI:L/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Hoch | good |

## Patch verfügbar (OSV)

- c6a01e289540971c4d0bfd8b91ee6f8438d66394 (Commit)
- 44b8b16267145fdfda66ab656df6e89b32ce69d4 (Commit)

## BSI-Hinweise (deutsch)

- [n8n: Mehrere Schwachstellen](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-3393) — _BSI-Einstufung: hoch_
  Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in n8n ausnutzen, um Sicherheitsmaßnahmen zu umgehen, Daten offenzulegen oder zu manipulieren oder Code auszuführen.

## Referenzen

- <https://github.com/n8n-io/n8n/security/advisories/GHSA-rx55-8qhx-4hwx>
- <https://www.vulncheck.com/advisories/n8n-before-2.39.6-and-2.40-x-before-2.40.1-session-token-leak-via-dynamic-credentials>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-103259) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_