Description
Bitwarden Server before 2026.5.0 contains a privilege escalation vulnerability that allows authenticated Custom users with ManageUsers permission to remove Admin accounts from an organization by exploiting a missing role hierarchy check in the bulk user-remove endpoint. Attackers can supply Admin organization-user IDs in a bulk DELETE request to bypass the guard enforced on the single-user removal path, effectively removing one or more Admin accounts from an organization.
CVSS breakdown
CVSS 4.0
Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Confidentiality (Vulnerable System)
None
Integrity (Vulnerable System)
High
Availability (Vulnerable System)
Low
Confidentiality (Subsequent System)
None
Integrity (Subsequent System)
None
Availability (Subsequent System)
None
CVSS 3.1
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
Low
Affected products
- bitwarden / server0 – 2026.5.0
References
- MISChttps://sanjokkarki.com.np/blog/bitwarden-bulk-remove-admin
- PATCHhttps://github.com/bitwarden/server/releases/tag/v2026.5.0
- PATCHhttps://github.com/bitwarden/server/pull/7526
- PATCHhttps://github.com/bitwarden/server/commit/901bb67157c0f80d369c40b76742fdf7623da4e4
- VENDOR_ADVISORYhttps://www.vulncheck.com/advisories/bitwarden-server-privilege-escalation-via-bulk-user-remove-endpoint