CVE-2026-43639CRITICAL 9.1EPSS p43.8%

CVE-2026-43639CVE-2026-43639

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).

Scoring

CVSS 3.19.1 (CRITICAL)
VectorCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
EPSS0.60% probability of exploitation · percentile 43.8% · 2026-06-19T12:03:05Z
Published2026-05-11
Last modified2026-05-16

Underlying weaknesses· 1

CWE-862

References

  1. https://github.com/bitwarden/server/commit/0918bfdda6f5eec391c69bd9074f6aef4eac0b1d
  2. https://github.com/bitwarden/server/pull/7372
  3. https://github.com/bitwarden/server/releases/tag/v2026.4.0
  4. https://sanjokkarki.com.np/blog/bitwarden-provider-takeover
  5. https://www.vulncheck.com/advisories/bitwarden-server-missing-authorization-via-provider-clients

1

TypeTargetConfidenceTier
WeaknessMissing Authorizationcwe-8620%live

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Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.