Performance Degradation Vulnerability in js-yaml by Nodeca
CVE-2026-59868

5.3MEDIUM

Key Information:

Vendor

Nodeca

Status
Js-yaml
Vendor
CVE Published:
8 July 2026

What is CVE-2026-59868?

The js-yaml library, a widely-used JavaScript YAML parser, is susceptible to a performance degradation issue when merge keys are utilized. In versions 5.0.0 to 5.2.0, complicated document structures that leverage merge keys can lead to increased CPU consumption. This vulnerability manifests particularly in scenarios where mappings recursively merge previous ones, resulting in potentially significant delays during document parsing. The issue has been effectively resolved in version 5.2.0.

Affected Version(s)

js-yaml >= 5.0.0, < 5.2.0

References

https://github.com/nodeca/js-yaml/security/advisories/GHS...
x_refsource_CONFIRM
https://github.com/nodeca/js-yaml/commit/3105455b81dee69e...
x_refsource_MISC
https://github.com/nodeca/js-yaml/releases/tag/5.2.0
x_refsource_MISC

CVSS V3.1

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.