CVE-2025-32379
MEDIUMCVE-2025-32379 is a medium-severity (CVSS 5) Cross-site Scripting (XSS) vulnerability in koa. O3 Security confirms whether CVE-2025-32379 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
XSS at ctx.redirect() function in Koajs
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
koanpmDescription
Koa is expressive middleware for Node.js using ES2017 async functions. In koa < 2.16.1 and < 3.0.0-alpha.5, passing untrusted user input to ctx.redirect() even after sanitizing it, may execute javascript code on the user who use the app. This issue is patched in 2.16.1 and 3.0.0-alpha.5.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | koa | all versions | 2.16.1 |
| 📦npm | koa | ≥ 3.0.0-alpha.1&&< 3.0.0-alpha.5 | 3.0.0-alpha.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for koa. 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 koa to 2.16.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-32379 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 CVE-2025-32379 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 CVE-2025-32379. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-32379 in your dependencies?
O3 detects CVE-2025-32379 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.