CVE-2026-101878: Bitwarden Server 2025.6.0 < 2025.6.0 Authentication Bypass via SSO Identifier Truncation
Description
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.
Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H · CWE-303
Tracked companies
Mapped from the CVE’s affected-product data, NVD CPE matches, vendor advisories or package feeds. A mapping means the vendor’s software is named, not that its hosted service was exposed.
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
bitwarden: bitwarden server
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- github.com/bitwarden/server/commit/27ae3d5455f723975fac03819eaeba8710666bc4 (opens in new tab)
- github.com/bitwarden/server/pull/7501 (opens in new tab)
- github.com/bitwarden/server/releases/tag/v2026.5.0 (opens in new tab)
- sanjokkarki.com.np/blog/bitwarden-sso-externalid-truncation (opens in new tab)
- www.vulncheck.com/advisories/bitwarden-server-authentication-bypass-via-sso-identifier-… (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)