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.
- CVSS 3.1
- 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.6% chance of exploitation in the next 30 days; higher than 47% of CVEs (scores of 2026-10-25)
- CWE
- CWE-407
- Published
- Modified
- Record from
- the NVD, synced
Affected
- nodeca:js-yaml
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-52cp-r559-cp3m | npm | js-yaml | >=3.0.0 <3.15.0 | 3.15.0 |
| GHSA-52cp-r559-cp3m | npm | js-yaml | >=4.0.0 <4.3.0 | 4.3.0 |
References
- 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
- https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m