CVE-2026-27803

Vaultwarden is an unofficial Bitwarden compatible server written in Rust, formerly known as bitwarden_rs. Prior to version 1.35.4, when a Manager has manage=false for a given collection, they can still perform several management operations as long as they have access to the collection. This issue has been patched in version 1.35.4.

Vaultwarden is an unofficial Bitwarden compatible server written in Rust, formerly known as bitwarden_rs. Prior to version 1.35.4, when a Manager has manage=false for a given collection, they can still perform several management operations as long as they have access to the collection. This issue has been patched in version 1.35.4.

Summary

Testing confirmed that even when a Manager has manage=false for a given collection, they can still perform the following management operations as long as they have access to the collection:

• PUT /api/organizations/<org_id>/collections/<col_id> succeeds (HTTP 200)
• PUT /api/organizations/<org_id>/collections/<col_id>/users succeeds (HTTP 200)
• DELETE /api/organizations/<org_id>/collections/<col_id> succeeds (HTTP 200)

Description

• The Manager guard checks only whether the user can access the collection, not whether they have manage privileges. This check is directly applied to management endpoints. src/auth.rs:816

  
  if !Collection::can_access_collection(&headers.membership, &col_id, &conn).await {
      err_handler!("The current user isn't a manager for this collection")
  }
  

• The can_access_collection function does not evaluate the manage flag. src/db/models/collection.rs:140

  
  pub async fn can_access_collection(member: &Membership, col_id: &CollectionId, conn: &DbConn) -> bool {
      member.has_status(MembershipStatus::Confirmed)
          && (member.has_full_access()
              || CollectionUser::has_access_to_collection_by_user(col_id, &member.user_uuid, conn).await
              || ...
  

• A separate management-permission check exists and includes manage validation, but it is not used during authorization for the affected endpoints. src/db/models/collection.rs:516

  
  pub async fn is_manageable_by_user(&self, user_uuid: &UserId, conn: &DbConn) -> bool {
      let Some(member) = Membership::find_confirmed_by_user_and_org(user_uuid, &self.org_uuid, conn).await else {
          return false;
      };
      if member.has_full_access() {
          return true;
      }
      ...
  

• The actual update and deletion endpoints only accept ManagerHeaders and do not perform additional manage checks. src/api/core/organizations.rs:608

  async fn put_organization_collection_update(..., headers: ManagerHeaders, ...)

src/api/core/organizations.rs:890

  async fn put_collection_users(..., headers: ManagerHeaders, ...)

src/api/core/organizations.rs:747

  async fn delete_organization_collection(..., headers: ManagerHeaders, ...)

Preconditions

• The attacker is a Manager within the target organization.
• The attacker has access to the target collection (assigned=true).
• The attacker’s permission for that collection is manage=false.
• A valid API access token has been obtained.

Steps to Reproduce

1. Confirm that the attacker’s current permissions for the target collection include manage=false. <img width="2015" height="636" alt="image" src="https://github.com/user-attachments/assets/58ddc733-e37c-4766-a980-b1ea1918ceb4" />

2. As a control test, verify that update operations fail for collections the attacker cannot access. <img width="2021" height="852" alt="image" src="https://github.com/user-attachments/assets/d8699442-2dfc-4d73-8940-ec10f4a175f0" />

3. Confirm that update operations succeed for the target collection where manage=false. <img width="2013" height="690" alt="image" src="https://github.com/user-attachments/assets/33d9845d-d18e-456c-a58c-e780911347a9" />

4. Use PUT /collections/{col_id}/users to set manage=true, confirming that the attacker can escalate their own privileges. <img width="2018" height="488" alt="image" src="https://github.com/user-attachments/assets/da8c5246-cf2a-46c2-9a25-e99d907f852d" />

5. Verify that deletion of the collection succeeds despite the Manager lacking management rights. <img width="2018" height="487" alt="image" src="https://github.com/user-attachments/assets/a97c8fb2-4f97-4c2a-a90b-9d95dbde84fd" />

Required Minimum Privileges

• Organization Manager role (Owner/Admin privileges are not required)
• Works even with access_all=false
• Only access rights to the target collection are required…

Vaultwarden is an unofficial Bitwarden compatible server written in Rust, formerly known as bitwarden_rs. Prior to version 1.35.4, when a Manager has manage=false for a given collection, they can still perform several management operations as long as they have access to the collection. This issue has been patched in version 1.35.4.

Vaultwarden is an unofficial Bitwarden compatible server written in Rust, formerly known as bitwarden_rs. Prior to version 1.35.4, when a Manager has manage=false for a given collection, they can still perform several management operations as long as they have access to the collection. This issue has been patched in version 1.35.4.

Summary

Testing confirmed that even when a Manager has manage=false for a given collection, they can still perform the following management operations as long as they have access to the collection:

• PUT /api/organizations/<org_id>/collections/<col_id> succeeds (HTTP 200)
• PUT /api/organizations/<org_id>/collections/<col_id>/users succeeds (HTTP 200)
• DELETE /api/organizations/<org_id>/collections/<col_id> succeeds (HTTP 200)

Description

• The Manager guard checks only whether the user can access the collection, not whether they have manage privileges. This check is directly applied to management endpoints. src/auth.rs:816

  
  if !Collection::can_access_collection(&headers.membership, &col_id, &conn).await {
      err_handler!("The current user isn't a manager for this collection")
  }
  

• The can_access_collection function does not evaluate the manage flag. src/db/models/collection.rs:140

  
  pub async fn can_access_collection(member: &Membership, col_id: &CollectionId, conn: &DbConn) -> bool {
      member.has_status(MembershipStatus::Confirmed)
          && (member.has_full_access()
              || CollectionUser::has_access_to_collection_by_user(col_id, &member.user_uuid, conn).await
              || ...
  

• A separate management-permission check exists and includes manage validation, but it is not used during authorization for the affected endpoints. src/db/models/collection.rs:516

  
  pub async fn is_manageable_by_user(&self, user_uuid: &UserId, conn: &DbConn) -> bool {
      let Some(member) = Membership::find_confirmed_by_user_and_org(user_uuid, &self.org_uuid, conn).await else {
          return false;
      };
      if member.has_full_access() {
          return true;
      }
      ...
  

• The actual update and deletion endpoints only accept ManagerHeaders and do not perform additional manage checks. src/api/core/organizations.rs:608

  async fn put_organization_collection_update(..., headers: ManagerHeaders, ...)

src/api/core/organizations.rs:890

  async fn put_collection_users(..., headers: ManagerHeaders, ...)

src/api/core/organizations.rs:747

  async fn delete_organization_collection(..., headers: ManagerHeaders, ...)

Preconditions

• The attacker is a Manager within the target organization.
• The attacker has access to the target collection (assigned=true).
• The attacker’s permission for that collection is manage=false.
• A valid API access token has been obtained.

Steps to Reproduce

1. Confirm that the attacker’s current permissions for the target collection include manage=false. <img width="2015" height="636" alt="image" src="https://github.com/user-attachments/assets/58ddc733-e37c-4766-a980-b1ea1918ceb4" />

2. As a control test, verify that update operations fail for collections the attacker cannot access. <img width="2021" height="852" alt="image" src="https://github.com/user-attachments/assets/d8699442-2dfc-4d73-8940-ec10f4a175f0" />

3. Confirm that update operations succeed for the target collection where manage=false. <img width="2013" height="690" alt="image" src="https://github.com/user-attachments/assets/33d9845d-d18e-456c-a58c-e780911347a9" />

4. Use PUT /collections/{col_id}/users to set manage=true, confirming that the attacker can escalate their own privileges. <img width="2018" height="488" alt="image" src="https://github.com/user-attachments/assets/da8c5246-cf2a-46c2-9a25-e99d907f852d" />

5. Verify that deletion of the collection succeeds despite the Manager lacking management rights. <img width="2018" height="487" alt="image" src="https://github.com/user-attachments/assets/a97c8fb2-4f97-4c2a-a90b-9d95dbde84fd" />

Required Minimum Privileges

• Organization Manager role (Owner/Admin privileges are not required)
• Works even with access_all=false
• Only access rights to the target collection are required…