CVE-2026-43639: Bitwarden Server < 2026.4.0 Missing Authorization via Provider Clients
High · CVSS 8.0 (CVSS 3.1)EPSS 0.60%, 48th percentilePublished Updated Assigner: VulnCheck
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).
Vector CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H · CWE-862
Tracked companies
Mapped from the CVE’s affected-product data, NVD CPE matches, vendor advisories or package feeds. A mapping means the vendor’s software is named, not that its hosted service was exposed.
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
bitwarden: server
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- github.com/bitwarden/server/commit/0918bfdda6f5eec391c69bd9074f6aef4eac0b1d (opens in new tab)
- github.com/bitwarden/server/pull/7372 (opens in new tab)
- github.com/bitwarden/server/releases/tag/v2026.4.0 (opens in new tab)
- sanjokkarki.com.np/blog/bitwarden-provider-takeover (opens in new tab)
- www.vulncheck.com/advisories/bitwarden-server-missing-authorization-via-provider-client… (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)