CVE-2026-42039 Axios: unbounded recursion in toFormData causes DoS via deeply nested request data
An attacker can crash the Node.js process by sending deeply nested request data to an application using the Axios library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42039?
CVE-2026-42039 is a medium-severity denial of service vulnerability in axios, published on 24 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, toFormData recursively walks nested objects with no depth limit, so a deeply nested value passed as request data crashes the Node.js process with a RangeError. This vulnerability is fixed in 1.15.1 and 0.31.1.
Which versions are affected by CVE-2026-42039?
4 open source packages ship an affected version, including axios. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
axios npm | All versions | 0.31.1 |
axios npm | All versions | 0.31.1 |
axios npm | From 1.0.0 | 1.15.1 |
axios npm | From 1.0.0 | 1.15.1 |
Products include Axios Axios.
How do I fix CVE-2026-42039?
Upgrade axios to a fixed version for your release line: 0.31.1 or 1.15.1.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-42039 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42039 exists.
Other vulnerabilities in axios
- CVE-2026-44494 Axios: Full Man-in-the-Middle via Prototype Pollution Gadget in `config.proxy`
- CVE-2026-44492 axios's shouldBypassProxy does not recognize IPv4-mapped IPv6 addresses, allowing NO_PROXY bypass (incomplete fix for CVE-2025-62718)
- CVE-2026-67320 axios before 0.33.0 Prototype Pollution via Node HTTP adapter
- CVE-2026-44487 Axios: Proxy-Authorization Credential Leak to Origin Server Across HTTP-to-HTTPS Redirect in Axios Node.js HTTP Adapter
- CVE-2025-27152 Possible SSRF and Credential Leakage via Absolute URL in axios Requests
Sources
Also known as CLEANSTART-2026-AL76346, CLEANSTART-2026-NR30483, CLSA-2026-1785291686, DEBIAN-CVE-2026-42039, ECHO-598a-bd90-49ac, GHSA-62hf-57xw-28j9 and 21 more.