Resource exhaustion in Nodeca Js-Yaml
CVE-2026-59870
js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 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. This issue is fixed in version 5.2.1.
EPSS: 0.004 (34.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
Affected products
- Nodeca Js-yaml — versions >= 5.0.0, < 5.2.1
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-59870?
- CVE-2026-59870 is a medium-severity vulnerability in Nodeca Js-Yaml, classified under Inefficient Algorithmic Complexity. CVSS score: 5.3/10. Published 2026-07-08.
- How severe is CVE-2026-59870?
- Medium severity. CVSS v3 base score is 5.3 out of 10.