CVE-2026-101878
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.26%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 7.7 HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.26% probability · 17th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-303
- Source
- disclosure@vulncheck.com
EPSS moved from 0.3% on 29 September 2026 to 0.3% on 26 October 2026.
References
- https://github.com/bitwarden/server/commit/27ae3d5455f723975fac03819eaeba8710666bc4
- https://github.com/bitwarden/server/pull/7501
- https://github.com/bitwarden/server/releases/tag/v2026.5.0
- https://sanjokkarki.com.np/blog/bitwarden-sso-externalid-truncation
- https://www.vulncheck.com/advisories/bitwarden-server-authentication-bypass-via-sso-identifier-truncation
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.