CVE-2026-43638: Bitwarden Server < 2026.4.1 Missing Authorization via Organization Cipher Import

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-11 · updated 2026-10-26
Weakness: CWE-862

Description

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.

Affected products

bitwarden server: before 2026.4.1 — fixed in 2026.4.1

How to fix

Upgrade to a fixed version: bitwarden server 2026.4.1. Check the vendor advisory for mitigations.

References

https://github.com/bitwarden/server/commit/ebbf6dd0fa752114c09d73abb48ce32a50476758
https://github.com/bitwarden/server/pull/7394
https://github.com/bitwarden/server/releases/tag/v2026.4.1
https://sanjokkarki.com.np/blog/bitwarden-import-org-bypass
https://www.vulncheck.com/advisories/bitwarden-server-missing-authorization-via-organization-cipher-import

Get alerted when CVE-2026-43638 or the next vulnerability affects your stack