High 7.5Published Sep 29, 2026

CVE-2026-101878Bitwarden Server 2025.6.0 < 2025.6.0 Authentication Bypass via SSO Identifier Truncation

Updated under an hour ago (2026-10-19 06:10 UTC)

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It affects bitwarden server. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.26%, higher than 16% of scored CVEs.

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Every CVE for bitwarden server

Exploited in the last 30 days

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: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-303
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.26% (percentile 16)
Assigned by: VulnCheck
NVD analysis: Awaiting Analysis
Record last updated: Oct 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

bitwarden bitwarden server bitwarden:server (from the name)	from 2025.6.0 before 2026.5.0	CNA record

References

https://sanjokkarki.com.np/blog/bitwarden-sso-externalid-truncationtechnical-description, exploit
https://github.com/bitwarden/server/releases/tag/v2026.5.0release-notes
https://github.com/bitwarden/server/pull/7501issue-tracking
https://github.com/bitwarden/server/commit/27ae3d5455f723975fac03819eaeba8710666bc4patch
https://www.vulncheck.com/advisories/bitwarden-server-authentication-bypass-via-sso-identifier-truncationthird-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.