---
title: "CVE-2026-101878: Bitwarden Server - Authentication Bypass"
description: "Bitwarden Server 2025.6.0 before 2026.5.0 contains a broken authentication caused by truncation of the @ExternalId parameter in User_ReadBySsoUserOrganizationIdExternalId stored procedure, letting users authenticate as other members with similar SSO identifiers, exploit requires SQL Server deployment with specific SSO identifiers."
url: https://panop.io/threat-heartbeat/CVE-2026-101878/
---

# CVE-2026-101878 Bitwarden Server - Authentication Bypass

Bitwarden Server 2025.6.0 before 2026.5.0 contains a broken authentication caused by truncation of the @ExternalId parameter in User\_ReadBySsoUserOrganizationIdExternalId stored procedure, letting users authenticate as other members with similar SSO identifiers, exploit requires SQL Server deployment with specific SSO identifiers.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.26% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-101878)

## Details

Type

Authentication Bypass

Impact

Broken Authentication

CVSS vector

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

Published

29 September 2026

Updated

15 October 2026

Weakness

[CWE-303](https://cwe.mitre.org/data/definitions/303.html)

## Vendor fix

Update to version 2026.5.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-101878](https://nvd.nist.gov/vuln/detail/CVE-2026-101878)
- [https://github.com/bitwarden/server/commit/27ae3d5455f723975fac03819eaeba8710666bc4](https://github.com/bitwarden/server/commit/27ae3d5455f723975fac03819eaeba8710666bc4)
- [https://github.com/bitwarden/server/pull/7501](https://github.com/bitwarden/server/pull/7501)
- [https://github.com/bitwarden/server/releases/tag/v2026.5.0](https://github.com/bitwarden/server/releases/tag/v2026.5.0)
- [https://sanjokkarki.com.np/blog/bitwarden-sso-externalid-truncation](https://sanjokkarki.com.np/blog/bitwarden-sso-externalid-truncation)
- [https://www.vulncheck.com/advisories/bitwarden-server-authentication-bypass-via-sso-identifier-truncation](https://www.vulncheck.com/advisories/bitwarden-server-authentication-bypass-via-sso-identifier-truncation)

[← All CVEs](https://panop.io/threat-heartbeat/)

## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

[Book a demo](https://panop.io/demo)