CVE-2026-43639
Bitwarden Server < 2026.4.0 Missing Authorization via Provider Clients
CVSS Score
8.0
EPSS Score
0.0%
EPSS Percentile
0th
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).
| CWE | CWE-862 |
| Vendor | bitwarden |
| Product | server |
| Published | May 11, 2026 |
| Last Updated | May 11, 2026 |
Stay Ahead of the Next One
Get instant alerts for bitwarden server
Be the first to know when new high vulnerabilities affecting bitwarden server are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
High
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
bitwarden / server
0 < 2026.4.0
References
sanjokkarki.com.np: https://sanjokkarki.com.np/blog/bitwarden-provider-takeover github.com: https://github.com/bitwarden/server/releases/tag/v2026.4.0 github.com: https://github.com/bitwarden/server/pull/7372 github.com: https://github.com/bitwarden/server/commit/0918bfdda6f5eec391c69bd9074f6aef4eac0b1d vulncheck.com: https://www.vulncheck.com/advisories/bitwarden-server-missing-authorization-via-provider-clients
Credits
Sanjok Karki