Vulnerability details
CVE-2026-59869
nodeca js-yaml
js-yaml: YAML merge-key chains can force quadratic CPU consumption
CVSS 3.1
7.5High
Official description
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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 7.5High | 3.1 | CVEProject cvelistV5 (CNA) (GitHub_M) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| nodeca | js-yaml | >= 3.0.0, < 3.15.0 | CVEProject cvelistV5 (CNA) |
| nodeca | js-yaml | >= 4.0.0, < 4.3.0 | CVEProject cvelistV5 (CNA) |
References and advisories
5- https://github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7 x_refsource_MISC
- https://github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4 x_refsource_MISC
- https://github.com/nodeca/js-yaml/releases/tag/3.15.0 x_refsource_MISC
- https://github.com/nodeca/js-yaml/releases/tag/4.3.0 x_refsource_MISC
- https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m x_refsource_CONFIRM
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Details
- Published
- 2026-07-08
- Last updated
- 2026-07-09
- State
- Published
- Assigner (CNA)
- GitHub_M
Exploit prediction (EPSS)
0.58%
Probability of exploitation in 30 days
48.1%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- Proof of concept
- Technical impact
- Partial
Weaknesses (CWE)
- CWE-407Inefficient Algorithmic Complexity