js-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing
js-yaml is a JavaScript YAML parser and dumper. Prior to 3.15.1, 4.3.1, and 5.2.1, YAML11_SCHEMA support for the !!omap tag in src/tag/sequence/omap.ts uses omapTag.addItem() to perform a linear duplicate-key scan on every insertion, causing O(n^2) CPU consumption when yaml.load() parses a crafted ordered-map document. In v3 and v4, !!omap is active and exploitable by default. v5 doesn't use !!omap by default, and the chances of activating it are very low.This issue is fixed in 3.15.1, 4.3.1, and 5.2.1.
CVE-2026-59870
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-59870
js-yaml
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "nodeca",
"product": "js-yaml",
"versions": [
{
"status": "affected",
"version": ">= 5.0.0, < 5.2.1"
},
{
"status": "affected",
"version": ">= 3.0.0, < 3.15.1"
},
{
"status": "affected",
"version": ">= 4.0.0, < 4.3.1"
}
]
}
]- Related CVEs
- CVE-2026-59870
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #9350 · Revision 1
- Added to Heist Feed
- Publisher date