CVE-2026-59869

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 73% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this weekElevated
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
7.5
EG Score
7.5(medium)
EPSS
27.1%
KEV
Not listed

Published

July 8, 2026

Last Modified

July 10, 2026

Advisory Details (3)

Auto-updated Jul 8, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github Patch Available🟡 PoC Available

YAML merge-key chains can force quadratic CPU consumption in js-yaml · Advisory · nodeca/js-yaml · GitHub

https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m
github_commit

commit 59423c6f8cdc (nodeca/js-yaml)

Fix landed in nodeca/js-yaml commit 59423c6f8cdc — awaiting tagged release

https://github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4
github_commit

commit 24f13e79ee13 (nodeca/js-yaml)

Fix landed in nodeca/js-yaml commit 24f13e79ee13 — awaiting tagged release

https://github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7

Vendor Advisories for CVE-2026-59869(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 12× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-11 20:35 UTCEG score recompute
  2. 2026-07-11 08:27 UTCEPSS rescore
  3. 2026-07-11 08:27 UTCEPSS rescore
  4. 2026-07-11 07:47 UTCEG score recompute
  5. 2026-07-10 18:59 UTCEG score recompute
  6. 2026-07-10 06:10 UTCEG score recompute
  7. 2026-07-09 19:10 UTCEPSS rescore
  8. 2026-07-09 19:10 UTCEPSS rescore
  9. 2026-07-09 17:23 UTCEG score recompute
  10. 2026-07-09 04:35 UTCEG score recompute
  11. 2026-07-08 15:46 UTCEG score recompute
  12. 2026-07-08 15:45 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-59869?
CVE-2026-59869 is a high vulnerability published on July 8, 2026. 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…
When was CVE-2026-59869 disclosed?
CVE-2026-59869 was first published in the National Vulnerability Database on July 8, 2026, with the most recent update on July 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59869 actively exploited?
CVE-2026-59869 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 27.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-59869?
CVE-2026-59869 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-59869?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59869, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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