CVE-2026-39865
MEDIUMCVE-2026-39865 is a medium-severity (CVSS 5.9) Uncontrolled Resource Consumption vulnerability in axios. O3 Security confirms whether CVE-2026-39865 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Axios HTTP/2 Session Cleanup State Corruption Vulnerability
Blast Radius
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Description
Axios is a promise based HTTP client for the browser and Node.js. Starting in version 1.13.0 and prior to 1.13.2, Axios HTTP/2 session cleanup logic contains a state corruption bug that allows a malicious server to crash the client process through concurrent session closures. The vulnerability exists in the Http2Sessions.getSession() method in lib/adapters/http.js. The session cleanup logic contains a control flow error when removing sessions from the sessions array. This vulnerability is fixed in 1.13.2.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | axios | ≥ 1.13.0&&< 1.13.2 | 1.13.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for axios. 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 axios to 1.13.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-39865 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-2026-39865 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-2026-39865. 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-2026-39865 in your dependencies?
O3 detects CVE-2026-39865 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.