GHSA-hh82-3pmq-7frp
MEDIUMNetty vulnerable to HTTP Response splitting from assigning header value iterator
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
io.netty:netty-codec-httpReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Impact
When calling DefaultHttpHeaders.set with an iterator of values (as opposed to a single given value), header value validation was not performed, allowing malicious header values in the iterator to perform HTTP Response Splitting.
Patches
The necessary validation was added in Netty 4.1.86.Final.
Workarounds
Integrators can work around the issue by changing the DefaultHttpHeaders.set(CharSequence, Iterator<?>) call, into a remove() call, and call add() in a loop over the iterator of values.
References
HTTP Response Splitting CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers
For more information
If you have any questions or comments about this advisory:
- Open an issue in [example link to repo](https://github.com/netty/netty)
- Email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.netty:netty-codec-http | ≥ 4.1.83.Final&&< 4.1.86.Final | 4.1.86.Final |
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 io.netty:netty-codec-http. 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 io.netty:netty-codec-http to 4.1.86.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-hh82-3pmq-7frp 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-hh82-3pmq-7frp 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-hh82-3pmq-7frp. 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-hh82-3pmq-7frp in your dependencies?
O3 detects GHSA-hh82-3pmq-7frp across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.