There is a possible ReDoS vulnerability in the query parameter filtering routines of Action Dispatch. This vulnerability has been assigned the CVE identifier CVE-2024-41128.
Carefully crafted query parameters can cause query parameter filtering to take an unexpected amount of time, possibly resulting in a DoS vulnerability. All users running an affected release should either upgrade or apply the relevant patch immediately.
Ruby 3.2 has mitigations for this problem, so Rails applications using Ruby 3.2 or newer are unaffected. Rails 8.0.0.beta1 depends on Ruby 3.2 or greater so is unaffected.
The fixed releases are available at the normal locations.
Users on Ruby 3.2 are unaffected by this issue.
Thanks to scyoon for the report and patches!