Possible Sensitive Session Information Leak in Active Storage

There is a possible sensitive session information leak in Active Storage. By
default, Active Storage sends a Set-Cookie header along with the user's
session cookie when serving blobs. It also sets Cache-Control to public.
Certain proxies may cache the Set-Cookie, leading to an information leak.

This vulnerability has been assigned the CVE identifier CVE-2024-26144.

Versions Affected: >= 5.2.0, < 7.1.0
Not affected: < 5.2.0, > 7.1.0
Fixed Versions: 7.0.8.1, 6.1.7.7

Impact

A proxy which chooses to caches this request can cause users to share
sessions. This may include a user receiving an attacker's session or vice
versa.

This was patched in 7.1.0 but not previously identified as a security
vulnerability.

All users running an affected release should either upgrade or use one of the
workarounds immediately.

Releases

The fixed releases are available at the normal locations.

Workarounds

Upgrade to Rails 7.1.X, or configure caching proxies not to cache the
Set-Cookie headers.

Credits

Thanks to tyage for reporting this!