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:,


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.


The fixed releases are available at the normal locations.


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


To aid users who aren’t able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.

  • 6-1-VULN.patch - Patch for 6.1 series
  • 7-0-VULN.patch - Patch for 7.0 series


Thanks to tyage for reporting this!

6-1-active-storage-cookie.patch (3.2 KB) 7-0-active-storage-cookie.patch (3.2 KB)