High · published August 1, 2026
axios versions from 0.28.0 before 0.33.0 and from 1.0.0 before 1.18.0 contain uncontrolled recursion in formDataToJSON (exposed as axios.formToJSON() and used internally when serializing FormData with Content-Type: application/json). When an application passes attacker-controlled FormData field names, a field name with thousands of nested bracket-delimited segments causes unbounded recursion in buildPath(), exhausting the JavaScript call stack (RangeError: Maximum call stack size exceeded) and causing denial of service for that request, or process termination in applications without appropriate error handling.
| Product | Versions | Fixed in |
|---|---|---|
| axios/axios | ≥ 0.28.0, < 0.33.0 | 0.33.0 |
| axios/axios | ≥ 1.0.0, < 1.18.0 | 1.18.0 |