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 ↗

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

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

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