Auth bypass in Bitwarden Server
CVE-2026-43638
Bitwarden Server prior to v2026.4.1 contains a missing authorization vulnerability that allows any authenticated user to write ciphers into an arbitrary organization via `POST /ciphers/import-organization` by submitting an empty `collections` array, which causes the server-side permission check to be skipped.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (8.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 9th percentile — 8.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- Bitwarden Server — versions 0
Weakness classification (CWE)
References
- sanjokkarki.com.np/blog/bitwarden-import-org-bypass (Exploit, technical-description, Third Party Advisory, exploit)
- github.com/bitwarden/server/releases/tag/v2026.4.1 (release-notes, Release Notes)
- github.com/bitwarden/server/pull/7394 (issue-tracking, Patch, Issue Tracking)
- github.com/bitwarden/server/commit/ebbf6dd0fa752114c09d73abb48ce32a50476758 (Patch, patch)
- www.vulncheck.com/advisories/bitwarden-server-missing-authorization-via-organiz… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-43638?
- CVE-2026-43638 is a medium-severity vulnerability in Bitwarden Server, classified under Missing Authorization. CVSS score: 5.4/10. Published 2026-05-11.
- How severe is CVE-2026-43638?
- Medium severity. CVSS v3 base score is 5.4 out of 10.