CVE-2026-59869
js-yaml: YAML merge-key chains can force quadratic CPU consumption
- State
- Published
- Severity
- 7.5 High
- Published
- Jul 8, 2026
- Updated
- Jul 9, 2026
- Reserved
- Jul 7, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | GitHub_M |
Weaknesses
- CWE-407 Inefficient Algorithmic Complexity
Affected Products
| Product | Versions |
|---|---|
js-yamlnodeca |
|
References
- https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m
- https://github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7
- https://github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4
- https://github.com/nodeca/js-yaml/releases/tag/3.15.0
- https://github.com/nodeca/js-yaml/releases/tag/4.3.0
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.