GHSA-qjwc-v72v-fq6r is a medium-severity (CVSS 4.8) CWE-444 vulnerability in io.undertow:undertow-core. O3 Security confirms whether GHSA-qjwc-v72v-fq6r is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
HTTP request smuggling in Undertow
Real-World Exposure
io.undertow:undertow-core☕io.undertow:undertow-coreReal-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
A flaw was found in Undertow. A regression in the fix for CVE-2020-10687 was found. HTTP request smuggling related to CVE-2017-2666 is possible against HTTP/1.x and HTTP/2 due to permitting invalid characters in an HTTP request. This flaw allows an attacker to poison a web-cache, perform an XSS attack, or obtain sensitive information from request other than their own. The highest threat from this vulnerability is to data confidentiality and integrity.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.undertow:undertow-core | ≥ 2.1.0&&< 2.1.6 | 2.1.6 |
| ☕Maven | io.undertow:undertow-core | all versions | 2.0.34 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.undertow:undertow-core. 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.undertow:undertow-core to 2.1.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qjwc-v72v-fq6r 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-qjwc-v72v-fq6r 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-qjwc-v72v-fq6r. 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-qjwc-v72v-fq6r in your dependencies?
O3 detects GHSA-qjwc-v72v-fq6r across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.