CVE-2026-42037
MEDIUMCVE-2026-42037 is a medium-severity (CVSS 5.3) vulnerability in axios. O3 Security confirms whether CVE-2026-42037 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Axios: CRLF Injection in multipart/form-data body via unsanitized blob.type in formDataToStream
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
axiosnpmDescription
Axios is a promise based HTTP client for the browser and Node.js. From 1.0.0 to before 1.15.1, the FormDataPart constructor in lib/helpers/formDataToStream.js interpolates value.type directly into the Content-Type header of each multipart part without sanitizing CRLF (\r\n) sequences. An attacker who controls the .type property of a Blob/File-like object (e.g., via a user-uploaded file in a Node.js proxy service) can inject arbitrary MIME part headers into the multipart form-data body. This bypasses Node.js v18+ built-in header protections because the injection targets the multipart body structure, not HTTP request headers. This vulnerability is fixed in 1.15.1.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | axios | ≥ 1.0.0&&< 1.15.1 | 1.15.1 |
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 1.15.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42037 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-2026-42037 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-2026-42037. 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-2026-42037 in your dependencies?
O3 detects CVE-2026-42037 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.