Vulnerability in Nodeca Js-Yaml
CVE-2026-59869
js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 before 3.15.0 and from 4.0.0 before 4.3.0, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one. This issue is fixed in versions 3.15.0 and 4.3.0.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (46.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.000
Affected products
- Nodeca Js-Yaml — versions >= 3.0.0, < 3.15.0, >= 4.0.0, < 4.3.0
Weakness classification (CWE)
References
- github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m (Exploit, Vendor Advisory)
- github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7 (Patch)
- github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4 (Patch)
- github.com/nodeca/js-yaml/releases/tag/3.15.0 (Release Notes)
- github.com/nodeca/js-yaml/releases/tag/4.3.0 (Release Notes)
Frequently asked questions
- What is CVE-2026-59869?
- CVE-2026-59869 is a high-severity vulnerability in Nodeca Js-Yaml, classified under Inefficient Algorithmic Complexity. CVSS score: 7.5/10. Published 2026-07-08.
- How severe is CVE-2026-59869?
- High severity. CVSS v3 base score is 7.5 out of 10.