CVE-2026-101878

high

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.

References

https://www.vulncheck.com/advisories/bitwarden-server-authentication-bypass-via-sso-identifier-truncation

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://euvd.enisa.europa.eu/vulnerability/EUVD-2026-88605

Details

Source: Mitre, NVD

Published: 2026-09-29

Updated: 2026-09-30

Risk Information

CVSS v2

Base Score: 7.1

Vector: CVSS2#AV:N/AC:H/Au:S/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 7.5

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

Severity: High

CVSS v4

Base Score: 7.7

Vector: 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

Severity: High

EPSS

EPSS: 0.00258