CVE-2026-67314: axios before 1.18.0 Prototype Pollution via auth subfields

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-08-01 · updated 2026-09-01
Weakness: CWE-1321

Description

axios versions >=1.15.2 and <1.18.0 contain prototype-pollution read-side gadgets in Basic auth subfield handling (lib/adapters/http.js and lib/helpers/resolveConfig.js). When an application is already affected by a separate prototype-pollution primitive and makes an axios request with an own auth object that omits the username and/or password properties, axios reads the inherited Object.prototype.username and Object.prototype.password values and uses them to construct an outbound 'Authorization: Basic ...' header. axios itself does not pollute prototypes. The practical impact is outbound request tampering: an attacker who controls the polluted prototype values can inject attacker-chosen Basic auth credentials or replace an existing Authorization header. Credential disclosure is only possible under additional application-specific conditions.

Affected products

axios: from 1.15.2 before 1.18.0 — fixed in 1.18.0

How to fix

Upgrade to a fixed version: axios 1.18.0. Check the vendor advisory for mitigations.

References

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