---
cve: "CVE-2026-101878"
severity: "HIGH"
cvss: 7.7
epss: "0.3%"
vendor: "Bitwarden"
kev: false
exploited: false
published: "2026-09-29 02:16:54"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-10-04T13:24:29+02:00"
---

# CVE-2026-101878

> 7.7 HIGH · 🧪 PoC

## Beschreibung

Bitwarden Server 2025.6.0 before 2026.5.0 declares the @ExternalId parameter of the User_ReadBySsoUserOrganizationIdExternalId stored procedure as NVARCHAR(50) while the column it queries stores NVARCHAR(300), silently truncating the SSO login identifier on SQL Server deployments and allowing a user whose identity-provider identifier begins with another organization member's full 50-character identifier to authenticate as that member and obtain a victim-scoped access token.

## CNA-Record (Kanon, cvelistV5)

- CNA: **VulnCheck**
- State: PUBLISHED
- Stand: 2026-10-01 19:19:18
- CNA-CVSS: **7.7** (`CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)

## CISA-Anreicherung (vulnrichment/ADP)

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

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- c3cabffccfe35004f5022f91f95cc0fb5e8aa7c4 (Commit)
- 27ae3d5455f723975fac03819eaeba8710666bc4 (Commit)

## BSI-Hinweise (deutsch)

- [Bitwarden: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-3610) — _BSI-Einstufung: mittel_
  Ein entfernter, authentisierter Angreifer kann eine Schwachstelle in Bitwarden ausnutzen, um Sicherheitsvorkehrungen zu umgehen.

## Referenzen

- <https://sanjokkarki.com.np/blog/bitwarden-sso-externalid-truncation>
- <https://github.com/bitwarden/server/releases/tag/v2026.5.0>
- <https://github.com/bitwarden/server/pull/7501>
- <https://github.com/bitwarden/server/commit/27ae3d5455f723975fac03819eaeba8710666bc4>
- <https://www.vulncheck.com/advisories/bitwarden-server-authentication-bypass-via-sso-identifier-truncation>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-101878) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_