Prerequisites
Vaultwarden Support String
doesn't matter
Vaultwarden Build Version
1.35.4
Deployment method
OS Package (apt, yum/dnf, pacman, apk, nix, ...)
Custom deployment method
No response
Reverse Proxy
cloudflared
Host/Server Operating System
Linux
Operating System Version
alpine linux
Clients
Browser Extension
Client Version
No response
Steps To Reproduce
Update Bitwarden browser extension to v2026.4.0 (standard on latest Nix-managed browsers).
Configure the extension to use a self-hosted Vaultwarden instance (v1.35.4).
Attempt to log in with a valid master password.
Expected Result
Successful authentication and login.
Actual Result
The extension fails with a generic "Unexpected Error." Inspection of the network console shows a 404 Not Found on the POST request to /identity/accounts/prelogin/password/.
Logs
Screenshots or Videos
No response
Additional Context
It appears the latest extension version has introduced a new subpath (/password/) at the end of the prelogin identity endpoint. While older extensions (v2026.3.0 and below) work perfectly by hitting /identity/accounts/prelogin, the new v4.0 client forces this undocumented route, which is currently missing in the Vaultwarden 1.35.x branch.
A temporary workaround using a downgraded 3.0 version of the extension
Prerequisites
Vaultwarden Support String
doesn't matter
Vaultwarden Build Version
1.35.4
Deployment method
OS Package (apt, yum/dnf, pacman, apk, nix, ...)
Custom deployment method
No response
Reverse Proxy
cloudflared
Host/Server Operating System
Linux
Operating System Version
alpine linux
Clients
Browser Extension
Client Version
No response
Steps To Reproduce
Update Bitwarden browser extension to v2026.4.0 (standard on latest Nix-managed browsers).
Configure the extension to use a self-hosted Vaultwarden instance (v1.35.4).
Attempt to log in with a valid master password.
Expected Result
Successful authentication and login.
Actual Result
The extension fails with a generic "Unexpected Error." Inspection of the network console shows a 404 Not Found on the POST request to /identity/accounts/prelogin/password/.
Logs
Screenshots or Videos
No response
Additional Context
It appears the latest extension version has introduced a new subpath (/password/) at the end of the prelogin identity endpoint. While older extensions (v2026.3.0 and below) work perfectly by hitting /identity/accounts/prelogin, the new v4.0 client forces this undocumented route, which is currently missing in the Vaultwarden 1.35.x branch.
A temporary workaround using a downgraded 3.0 version of the extension