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Vulnerability record · CVE-2026-43639 · published 11 May 2026

CVE-2026-43639: Bitwarden server missing authorization vulnerability

Bitwarden · Server

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).

8.9 CVSS 4.0 High EPSS 0.84% · top 43.8% CWE-862 · Missing authorization
8.9CVSS 4.0 base score
0.84%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
5References, 1 tagged exploit
14 Jul 2026Last modified by NVD

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).

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/bitwarden/server/commit/0918bfdda6f5eec391c69bd9074f6aef4eac0b1d Patch
https://github.com/bitwarden/server/pull/7372 Issue TrackingPatch
https://github.com/bitwarden/server/releases/tag/v2026.4.0 Release Notes
https://sanjokkarki.com.np/blog/bitwarden-provider-takeover ExploitThird Party Advisory
https://www.vulncheck.com/advisories/bitwarden-server-missing-authorization-via-provider-clients Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.3CVE-2026-60104Bitwarden server insecure direct object reference vulnerabilityBitwarden Server before 2026.6.0 does not verify that the email in a POST /auth-requests/admin-request body belongs to the authenticated caller, allo…EPSS 0.37%8.6CVE-2026-43640Bitwarden server vulnerabilityBitwarden Server prior to v2026.4.1 does not require master-password re-authentication when retrieving or rotating an organization's SCIM API key, al…EPSS 0.71%7.5CVE-2020-15879Bitwarden server server-side request forgery (ssrf) vulnerabilityBitwarden Server 1.35.1 allows SSRF because it does not consider certain IPv6 addresses (ones beginning with fc, fd, fe, or ff, and the :: address) a…EPSS 2.7%7.5CVE-2019-19766Bitwarden server vulnerabilityThe Bitwarden server through 1.32.0 has a potentially unwanted KDF.EPSS 1.3%7.1CVE-2026-57520Bitwarden server missing authorization vulnerabilityBitwarden Server before 2026.5.0 contains a privilege escalation vulnerability that allows authenticated Custom users with ManageUsers permission to …EPSS 0.64%5.3CVE-2026-57521Bitwarden server missing authorization vulnerabilityBitwarden Server before 2026.5.0 contains a broken access control vulnerability that allows any authenticated user to access arbitrary organization b…EPSS 0.43%5.3CVE-2026-43638Bitwarden server missing authorization vulnerabilityBitwarden Server prior to v2026.4.1 contains a missing authorization vulnerability that allows any authenticated user to write ciphers into an arbitr…EPSS 0.33%2.3CVE-2026-57522Bitwarden server injection vulnerabilityBitwarden Server before 2026.5.0 contains a JSON injection vulnerability in IntegrationTemplateProcessor.ReplaceTokens(), which substitutes user-cont…EPSS 0.46%

Source: NIST National Vulnerability Database (record CVE-2026-43639), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.