CVE-2026-101900 Axios: Fetch Adapter Header Injection via Inherited FormData getHeaders
Prototype pollution allows attackers to inject malicious headers into Axios fetch requests, potentially bypassing security controls or altering request behavior.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-101900?
CVE-2026-101900 is a medium-severity code injection vulnerability in axios, published on 28 Sep 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. From 1.12.0 until 1.20.0, ResolveConfig reads inherited Symbol.toStringTag, append, and getHeaders properties while resolving FormData headers. A separate same-process prototype-pollution flaw supplies an array or non-plain class instance whose inherited properties make it appear FormData-like; plain objects are blocked. The inherited getHeaders function can return attacker-controlled headers that resolveConfig merges into a fetch adapter request. Attacker-controlled headers can alter authorization, cache, metadata-service, or application-specific request behavior. This issue is fixed in version 1.20.0.
Which versions are affected by CVE-2026-101900?
2 open source packages ship an affected version, including axios.
| Package | Affected | Fixed in |
|---|---|---|
axios npm | From 1.12.0 | 1.20.0 |
axios npm | From 1.12.0 | 1.20.0 |
How do I fix CVE-2026-101900?
Upgrade axios to 1.20.0 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-101900 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101900 exists.
Sources
Also known as CLEANSTART-2026-AM75023, CLEANSTART-2026-MF48068, CLEANSTART-2026-RK00164, DEBIAN-CVE-2026-101900, ECHO-6b1e-ec03-9a56, GHSA-4hqw-qxg8-jxx2 and 16 more.