CVE-2026-59870

Summary

js-yaml is a JavaScript YAML parser and dumper. Prior to 3.15.1, 4.3.1, and 5.2.1, YAML11_SCHEMA support for the !!omap tag in src/tag/sequence/omap.ts uses omapTag.addItem() to perform a linear duplicate-key scan on every insertion, causing O(n^2) CPU consumption when yaml.load() parses a crafted ordered-map document. In v3 and v4, !!omap is active and exploitable by default. v5 doesn't use !!omap by default, and the chances of activating it are very low.This issue is fixed in 3.15.1, 4.3.1, and 5.2.1.

Affected Software

VendorProductVersion RangeStatus
nodecajs-yaml>= 5.0.0, < 5.2.1affected
nodecajs-yaml>= 3.0.0, < 3.15.1affected
nodecajs-yaml>= 4.0.0, < 4.3.1affected

Weaknesses

  • CWE-407: CWE-407: Inefficient Algorithmic Complexity

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: yes
    • Technical Impact: partial

Additional References

References