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TI-2026-31741 Aliases CVE-2026-43639GHSA-79fq-fw2p-vq3j

Bitwarden Server < 2026.4.0 Missing Authorization via Provider Clients

Priority HIGH 74CWE-862Published · Updated

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-862.

Summary

Bitwarden Server prior to v2026.4.0 contains a missing authorization vulnerability that allows a provider service user to add an arbitrary organization to their provider via `POST /providers/{providerId}/clients/existing`, resulting in takeover of the target organization; self-hosted installations are unaffected as this endpoint is restricted to Cloud via SelfHosted(NotSelfHostedOnly = true).

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00596 48th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA and NVD
Fix Fixed server (bitwarden): 2026.4.0

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
bitwardenserverbefore 2026.4.02026.4.0Patch availableCNA
  • server Vendorbitwarden Affected before 2026.4.0 Fixed in 2026.4.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:bitwarden:server:*:*:*:*:*:*:*:*before 2026.4.0Vulnerablebitwarden
  • cpe:2.3:a:bitwarden:server:*:*:*:*:*:*:*:* Versions before 2026.4.0 Vulnerable ·bitwarden

Remediation

  • Fix · CNA server (bitwarden) Fixed in 2026.4.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-43639
  2. 2026-10-03 Alias added: GHSA-79fq-fw2p-vq3j
  3. 2026-10-25 EPSS moved to the below the 50th percentile

References

Exploit 1

Patch 2

Other 1

  • TI-2026-42828 Bitwarden Server < 2026.6.0 Authorization Bypass via Admin Auth Request CVSS 4.0CRITICAL 9.3
  • TI-2026-31742 Bitwarden Server < 2026.4.1 Authentication Bypass via SCIM API Key CVSS 4.0HIGH 8.6
  • TI-2026-41410 Bitwarden Server < 2026.5.0 Privilege Escalation via Bulk User Remove Endpoint CVSS 4.0HIGH 7.1
  • TI-2026-41411 Bitwarden Server < 2026.5.0 Broken Access Control via PreviewInvoiceController CVSS 4.0MEDIUM 5.3
  • TI-2026-31740 Bitwarden Server < 2026.4.1 Missing Authorization via Organization Cipher Import CVSS 4.0MEDIUM 5.3
  • TI-2026-41412 Bitwarden Server < 2026.5.0 JSON Injection via Webhook Templates CVSS 4.0LOW 2.3
See all 8 →

Sources

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