Bitwarden Server before 2026.10.1 on Entity Framework backends contains an authorization bypass vulnerability that allows organization members to add ciphers to collections they cannot edit. Attackers can call POST /api/ciphers/create, where a nulled UserId is treated as administrative, to inject vault items synced to read-only or inaccessible collections' members.
Fix
Patch, vendor advisory and mitigation references on NVD 2
- https://github.com/bitwarden/server/commit/9030c42bf7d8f9ac2ff9fee85c39588d5eb81499 patch
- https://github.com/bitwarden/server/pull/8482 patch, issue-tracking
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 5.3 · bitwardenNVD modified 2026-10-30 11:30
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 8
- https://github.com/bitwarden/server/commit/9030c42bf7d8f9ac2ff9fee85c39588d5eb81499 patch
- https://github.com/bitwarden/server/pull/8482 patch, issue-tracking
- https://github.com/bitwarden/server/blob/v2026.10.0/src/Infrastructure.EntityFramework/Vault/Repositories/CipherRepository.cs#L112 technical-description
- https://github.com/bitwarden/server/blob/v2026.10.0/src/Api/Vault/Controllers/CiphersController.cs#L355 technical-description
- https://github.com/bitwarden/server/releases/tag/v2026.10.1 release-notes
- https://abraxaslabs.tech/research/bitwarden-cipher-create-acl third-party-advisory
- https://github.com/bitwarden/server product
- https://www.vulncheck.com/advisories/bitwarden-server-before-2026.10.1-authorization-bypass-via-post-api-ciphers-create third-party-advisory