CVE-2026-101909: axios Prototype Pollution

Vulnerability summary

CVE-2026-101909 is a high (CVSS 8.3) Prototype Pollution vulnerability in axios. EPSS estimates a 0.35% chance of exploitation in the next 30 days, higher than 27.5% of scored vulnerabilities.

Timeline

1. 28-09-2026
   PublishedVulnerability first disclosed.
2. 01-10-2026
   Last modifiedVulnerability information updated.

Description

Axios is a promise-based HTTP client for the browser and Node.js. From 0.28.0 until 0.34.0 and 1.15.1 until 1.20.0, ToFormData processes inherited serialization options and visitor properties supplied through prototype pollution. A separate same-process prototype-pollution flaw supplies inherited dots, indexes, metaTokens, maxDepth, visitor, or Blob values before object serialization. The inherited options alter toFormData field naming and data interpretation, maxDepth can force request failure, Blob changes value handling, and a polluted visitor can execute when an attacker already has the stronger ability to inject a function. Serialized field naming and data interpretation can change, maxDepth can cause request failure, Blob can alter value handling, and a polluted visitor can execute under the stronger function-injection primitive. This issue is fixed in versions 0.34.0 and 1.20.0.

• CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.