# yayson (npm) vulnerabilities

1 known vulnerability (1 critical), with the versions each affects and the releases that fix them.

## At a glance

- Latest release: 4.4.0 (Sep 15, 2026): no advisory affects it
- Newest unaffected release: 4.4.0 (Sep 15, 2026), the latest release
- Weekly downloads: 5,050
- Dependents: 0
- Releases: 29 since 1.0.0 (Oct 7, 2014)
- Registry: https://www.npmjs.com/package/yayson
- Releases read: Nov 8, 2026

## Version timeline

Affected versions per advisory, in version order:

- CVE-2026-61534: 1.0.0 to 4.2.0 (4.3.0 is outside it)

## Advisories (1)

### [CVE-2026-61534](https://cve.now/CVE-2026-61534): Yayson: Prototype pollution in the Store/LegacyStore deserialization

- Severity: Critical 9.1
- Published: Sep 14, 2026
- Affected: fixed in 4.3.0.
- Fixed in 4.3.0 (released Jun 22, 2026, 84 days before disclosure).
- The latest release, 4.4.0, is not affected.
- 60% of yayson downloads last week were affected versions (3.6K).

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