Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV N L N N U N N L 5.3 .0038 31.1 —
AFFECTED Product Versions Fixed js-yaml >= 4.0.0, < 4.2.0 – —
TIMELINE Jun 9 Reserved by GitHub_M Jun 22 EXPLOIT PUBLISHED — CVE-2026-53550 (nodeca js-yaml). Public exploit reference added. Jun 22 Published (CNA: GitHub_M)
js-yaml is a JavaScript YAML parser and dumper. Prior to 4.2.0 and 3.15.0, a crafted YAML document can trigger algorithmic CPU exhaustion in js-yaml merge-key processing (<<) by repeating the same alias many times in a merge sequence. This causes quadratic parse-time behavior relative to input size and can block a Node.js worker/event loop for seconds with a relatively small payload (tens of KB), resulting in denial of service. The issue is in merge handling inside lib/loader.js. This vulnerability is fixed in 4.2.0 and 3.15.0.
| Date | Event | Detail |
|---|---|---|
| June 9, 2026 | Reserved | Reserved by GitHub_M |
| June 22, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-53550 (nodeca js-yaml). Public exploit reference added. |
| June 22, 2026 | Published | Published (CNA: GitHub_M) |
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|---|---|---|---|
| nodeca | js-yaml | — | >= 4.0.0, < 4.2.0 | — |
Authoritative record: CVE-2026-53550 at cve.org
Vendors: nodeca
Weaknesses: CWE-407
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-53550 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.