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TI-2026-65186 Aliases CVE-2026-101878GHSA-2fcc-4gv4-mvr7

Bitwarden Server 2025.6.0 < 2025.6.0 Authentication Bypass via SSO Identifier Truncation

Priority HIGH 69CWE-303Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
High
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00258 17th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix Fixed bitwarden server (bitwarden): 2026.5.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
bitwardenbitwarden server2025.6.0 to before 2026.5.02026.5.0Patch availableCNA
  • bitwarden server Vendorbitwarden Affected 2025.6.0 to before 2026.5.0 Fixed in 2026.5.0 Patch available CNA

Remediation

  • Fix · CNA bitwarden server (bitwarden) Fixed in 2026.5.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-101878
  2. 2026-10-03 Alias added: GHSA-2fcc-4gv4-mvr7

References

Exploit 1

Patch 1

Other 2

  • TI-2026-42828 Bitwarden Server < 2026.6.0 Authorization Bypass via Admin Auth Request CVSS 4.0CRITICAL 9.3
  • TI-2026-31741 Bitwarden Server < 2026.4.0 Missing Authorization via Provider Clients CVSS 4.0HIGH 8.9
  • TI-2026-31742 Bitwarden Server < 2026.4.1 Authentication Bypass via SCIM API Key CVSS 4.0HIGH 8.6
  • TI-2023-12564 Bitwarden through 2023.2.1 offers password auto-fill when the second-level domain… CVSS 3.1HIGH 7.5
  • TI-2023-12369 Bitwarden Windows desktop application versions prior to v2023.4.0 store biometric keys in… CVSS 3.1HIGH 7.1
  • TI-2026-41410 Bitwarden Server < 2026.5.0 Privilege Escalation via Bulk User Remove Endpoint CVSS 4.0HIGH 7.1
See all 16 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences