# CVE-2026-43639: Bitwarden Server < 2026.4.0 Missing Authorization via Provider Clients

> CVE-2026-43639: Bitwarden Server < 2026.4.0 Missing Authorization via Provider Clients. CVSS 8.0 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-43639
Last updated: 2026-07-14T21:16:54Z

- Published: 2026-05-11 17:14 UTC · Updated: 2026-07-14 21:16 UTC · Assigner: VulnCheck
- CVSS: 8.0 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
- EPSS: 0.60%, 48th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-862

## 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).

## Affected vendors and products

- bitwarden: server

## Tracked companies

- [Bitwarden](https://rewindex.com/company/bitwarden.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-43639)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-43639)
- [https://github.com/bitwarden/server/commit/0918bfdda6f5eec391c69bd9074f6aef4eac0b1d](https://github.com/bitwarden/server/commit/0918bfdda6f5eec391c69bd9074f6aef4eac0b1d)
- [https://github.com/bitwarden/server/pull/7372](https://github.com/bitwarden/server/pull/7372)
- [https://github.com/bitwarden/server/releases/tag/v2026.4.0](https://github.com/bitwarden/server/releases/tag/v2026.4.0)
- [https://sanjokkarki.com.np/blog/bitwarden-provider-takeover](https://sanjokkarki.com.np/blog/bitwarden-provider-takeover)
- [https://www.vulncheck.com/advisories/bitwarden-server-missing-authorization-via-provider-clients](https://www.vulncheck.com/advisories/bitwarden-server-missing-authorization-via-provider-clients)

---

_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


---
Canonical: https://rewindex.com/cve/CVE-2026-43639 · Markdown: https://rewindex.com/cve/CVE-2026-43639.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-43639 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T04:06:21.611Z