Possible ReDoS vulnerability in Accept header parsing in Action Dispatch

There is a possible ReDoS vulnerability in the Accept header parsing routines
of Action Dispatch. This vulnerability has been assigned the CVE identifier
CVE-2024-26142.

Versions Affected: >= 7.1.0, < 7.1.3.1
Not affected: < 7.1.0
Fixed Versions: 7.1.3.1

Impact

Carefully crafted Accept headers can cause Accept header parsing in Action
Dispatch to take an unexpected amount of time, possibly resulting in a DoS
vulnerability. All users running an affected release should either upgrade or
use one of the workarounds immediately.

Ruby 3.2 has mitigations for this problem, so Rails applications using Ruby
3.2 or newer are unaffected.

Releases

The fixed releases are available at the normal locations.

Workarounds

There are no feasible workarounds for this issue.

Patches

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.

• 7-1-accept-redox.patch - Patch for 7.1 series

Credits

Thanks svalkanov for the report and patch!