CVE-2026-67319: axios Prototype Pollution

Vulnerability summary

CVE-2026-67319 is a medium (CVSS 6.3) Prototype Pollution vulnerability in axios. EPSS estimates a 0.32% chance of exploitation in the next 30 days, higher than 23.2% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 01-08-2026
   PublishedVulnerability first disclosed.
2. 03-08-2026
   Last modifiedVulnerability information updated.

Description

axios before 0.33.0 (and 1.x before 1.18.0) can consume inherited properties from nested request option objects when the JavaScript process's Object.prototype has already been polluted by another component. While the top-level merged config uses a null prototype, nested plain objects such as auth and paramsSerializer are cloned into ordinary objects and read without own-property checks. When an application passes placeholder nested objects such as auth: {} or paramsSerializer: {}, inherited username/password values can cause silent injection of an Authorization: Basic header, and inherited encode/serialize values can alter query-string serialization (full serializer replacement requires a function-valued pollution primitive). This is exploitable only in the presence of pre-existing prototype pollution.

• 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.