Rails has possible ReDoS vulnerability in Accept header parsing in Action Dispatch

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

• CVE-2024-26142: 1.50% estimated exploitation activity in the next 30 days; percentile 74.27 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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.…

Published by the source

27 Feb 2024, 21:41 UTC

Last modified by the source

21 Mar 2026, 05:30 UTC

Source last checked

26 Oct 2026, 15:51 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jjhx-jhvp-74wq

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2024-26142

Advisory: Rails has possible ReDoS vulnerability in Accept header parsing in Action Dispatch
IDs: CVE-2024-26142, GHSA-jjhx-jhvp-74wq
Record: https://patchnext.com/advisories/cve-2024-26142 (revision 1, source checked 26 Oct 2026, 15:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: actionpack 7.1.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems actionpack: affected >= 7.1.0, < 7.1.3.1; fixed in 7.1.3.1

## Suggested inspection (read-only)
- RubyGems actionpack: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on actionpack.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-jjhx-jhvp-74wq (GitHub-reviewed advisory GHSA-jjhx-jhvp-74wq lists affected ranges: RubyGems actionpack >=7.1.0 <7.1.3.1)

Commands are suggestions: review each one before running it.