CVE-2026-43639

Bitwarden Server < 2026.4.0 Missing Authorization via Provider Clients

Published May 11, 2026 CVSS 4.0 · 8.9 High EPSS < 1% KEV · Not listed
Description
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).

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:bitwarden:server:*:*:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Bitwarden
Bitwarden server
Vendors & Products Bitwarden
Bitwarden server
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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).
Title Bitwarden Server < 2026.4.0 Missing Authorization via Provider Clients
Weaknesses CWE-862
References
Metrics cvssV3_1

{'score': 8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H'}

cvssV4_0

{'score': 8.9, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Nov 8, 2026, 2:03 PM
Reserved
May 1, 2026, 6:22 PM
Status
Analyzed
Published
May 11, 2026, 6:16 PM
Modified
Oct 26, 2026, 6:10 PM