Browser extension fails to initialize after sign-out on Chrome 147

Incident Summary

On 8 April 2026, users reported that the Passbolt browser extension failed to start when navigating to the Passbolt API URL after signing out. The issue primarily affected users on Chrome and Edge 147 and was present across extension versions 5.10 and 5.11.

While the extension appeared unresponsive, a temporary workaround was available: toggling the extension off and on or restarting the browser restored access. Further investigation revealed the impact was broader than initially reported, the extension could also become unresponsive during navigation within the application, particularly in the administration workspace.

A fix was implemented across both the browser extension (5.11.1) and the API (5.11.0) to ensure full compatibility with these browser changes.

Timeline

• 8 Apr, 09:56: Incident reported and investigation started.
• 8 Apr, 11:26: Root cause identified; fixes in progress.
• 8 Apr, 20:15: Extensions submitted for review.
• 9 Apr, 09:00: Extension 5.11.1 published to the store.
• 9 Apr, 10:00: API 5.11.0 released; monitoring started.
• 9 Apr, 13:00: Incident resolved.

Root Cause

The issue was triggered by a change in how Chromium 147 manages page caching, specifically the Back/Forward Cache (BFCache). This browser-level update affected the extension's ability to initialise properly when users navigated between cached pages, such as from the application to the login page, or between pages served by the API and pages served by the browser extension.

This defect had gone undetected because:

• The canary browser test suite did not cover this scenario.
• Whether this specific BFCache behaviour is intentional or a regression in Chromium 147 is still unclear, as the application explicitly signals that it should not be cached by this mechanism.

We have since addressed the issue and are actively working to add safeguards to prevent similar regressions in the future.

Thank you for your patience and understanding. We apologise for the inconvenience this may have caused.