GHSA-vfm5-rmrh-j26v
Possible Content Security Policy bypass in Action Dispatch
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
actionpack💎actionpack💎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
There is a possible Cross Site Scripting (XSS) vulnerability in the content_security_policy helper in Action Pack.
Impact
Applications which set Content-Security-Policy (CSP) headers dynamically from untrusted user input may be vulnerable to carefully crafted inputs being able to inject new directives into the CSP. This could lead to a bypass of the CSP and its protection against XSS and other attacks.
Releases
The fixed releases are available at the normal locations.
Workarounds
Applications can avoid setting CSP headers dynamically from untrusted input, or can validate/sanitize that input.
Credits
Thanks to ryotak for the report!
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | actionpack | ≥ 5.2.0&&< 7.0.8.7 | 7.0.8.7 |
| 💎RubyGems | actionpack | ≥ 7.1.0&&< 7.1.5.1 | 7.1.5.1 |
| 💎RubyGems | actionpack | ≥ 7.2.0&&< 7.2.2.1 | 7.2.2.1 |
| 💎RubyGems | actionpack | ≥ 8.0.0&&< 8.0.0.1 | 8.0.0.1 |
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 7.0.8.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vfm5-rmrh-j26v 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-vfm5-rmrh-j26v 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-vfm5-rmrh-j26v. 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-vfm5-rmrh-j26v in your dependencies?
O3 detects GHSA-vfm5-rmrh-j26v across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.