Axios: Fetch Adapter Header Injection via Inherited FormData getHeaders
At a glance
Severity
MEDIUM 6.9
EPSS
EPSS 0.55 % · percentile 46 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
GitHub_M
NVD status
Awaiting Analysis
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.
