GHSA-g8ww-46x2-2p65
HIGHGHSA-g8ww-46x2-2p65 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in actionpack. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-g8ww-46x2-2p65 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Denial of Service in Action Dispatch
Real-World Exposure
actionpack💎actionpackReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Impact
There is a possible Denial of Service vulnerability in Action Dispatch. Carefully crafted Accept headers can cause the mime type parser in Action Dispatch to do catastrophic backtracking in the regular expression engine.
Releases
The fixed releases are available at the normal locations.
Workarounds
The following monkey patch placed in an initializer can be used to work around the issue.
module Mime
class Type
MIME_REGEXP = /\A(?:\*\/\*|#{MIME_NAME}\/(?:\*|#{MIME_NAME})(?>\s*#{MIME_PARAMETER}\s*)*)\z/
end
end
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.
- 6-0-Prevent-catastrophic-backtracking-during-mime-parsin.patch - Patch for 6.0 series
- 6-1-Prevent-catastrophic-backtracking-during-mime-parsin.patch - Patch for 6.1 series
Please note that only the 6.1.Z, 6.0.Z, and 5.2.Z series are supported at present. Users of earlier unsupported releases are advised to upgrade as soon as possible as we cannot guarantee the continued availability of security fixes for unsupported releases.
Credits
Thanks to Security Curious [email protected] for reporting this!
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | actionpack | ≥ 6.0.0&&< 6.0.3.7 | 6.0.3.7 |
| 💎RubyGems | actionpack | ≥ 6.1.0&&< 6.1.3.2 | 6.1.3.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for actionpack. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update actionpack to 6.0.3.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g8ww-46x2-2p65 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-g8ww-46x2-2p65 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-g8ww-46x2-2p65. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is GHSA-g8ww-46x2-2p65 in your dependencies?
O3 detects GHSA-g8ww-46x2-2p65 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.