CVE-2026-59868
js-yaml: YAML merge-key chains can force quadratic CPU consumption
CVSS Score
5.3
EPSS Score
0.3%
EPSS Percentile
21th
js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.0, when merge keys are enabled, 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 version 5.2.0.
| CWE | CWE-407 |
| Vendor | nodeca |
| Product | js-yaml |
| Published | Jul 8, 2026 |
| Last Updated | Jul 9, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low
Affected Versions
nodeca / js-yaml
>= 5.0.0, < 5.2.0