high7.5
CVE-2026-59869
js-yaml: YAML merge-key chains can force quadratic CPU consumption
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | js-yaml | >= 3.0.0, < 3.15.0 | 3.15.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Nodeca | Js-Yaml | from 3.0.0 before 3.15.0 from 4.0.0 before 4.3.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-52cp-r559-cp3m
- https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m
- https://nvd.nist.gov/vuln/detail/CVE-2026-59869
- 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