GHSA-5hq2-xf89-9jxq
MEDIUMGHSA-5hq2-xf89-9jxq is a medium-severity (CVSS 6.1) Open Redirect vulnerability in actionpack. O3 Security confirms whether GHSA-5hq2-xf89-9jxq is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Possible Open Redirect Vulnerability in Action Pack
Real-World Exposure
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
There is a possible Open Redirect Vulnerability in Action Pack.
Versions Affected: >= v6.1.0.rc2 Not affected: < v6.1.0.rc2 Fixed Versions: 6.1.3.2
Impact
This is similar to CVE-2021-22881. Specially crafted Host headers in combination with certain "allowed host" formats can cause the Host Authorization middleware in Action Pack to redirect users to a malicious website.
Since rails/rails@9bc7ea5, strings in config.hosts that do not have a leading dot are converted to regular expressions without proper escaping. This causes, for example, config.hosts << "sub.example.com" to permit a request with a Host header value of sub-example.com.
Releases
The fixed releases are available at the normal locations.
Workarounds
The following monkey patch put in an initializer can be used as a workaround.
class ActionDispatch::HostAuthorization::Permissions
def sanitize_string(host)
if host.start_with?(".")
/\A(.+\.)?#{Regexp.escape(host[1..-1])}\z/i
else
/\A#{Regexp.escape host}\z/i
end
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.
- 6-1-open-redirect.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 Jonathan Hefner (https://hackerone.com/jonathanhefner) for reporting this bug!
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | actionpack | ≥ 6.1.0.rc2&&< 6.1.3.2 | 6.1.3.2 |
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 6.1.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5hq2-xf89-9jxq 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-5hq2-xf89-9jxq 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-5hq2-xf89-9jxq. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-5hq2-xf89-9jxq in your dependencies?
O3 detects GHSA-5hq2-xf89-9jxq across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.