CVE-2026-43639CWE-862

Bitwarden Server < 2026.4.0 Missing Authorization via Provider Clients

High · published May 11, 2026

CVSS v4.0
8.9
EPSS
1%
Percentile
57.5
In the wild
Unconfirmed
What it is

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).

The record
Technical detail
CVSS v4.0
8.9 · HIGH
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
EPSS
0.00841 · 57.5th percentile
Weakness
CWE-862 · Missing Authorization
Published
2026-05-11T17:14Z
EPSS history
Timeline
  • 11 MAY 17:14Z
    Bitwarden Server < 2026.4.0 Missing Authorization via Provider Clients
    cvelistv5