js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 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. This issue is fixed in version 5.2.1.
CVE-2026-59870
HIGHNVD 7.57.5—Trending — 5 sources updated this weekElevated
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 79% 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, nvd
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
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 21.0%
- KEV
- Not listed
Published
July 8, 2026
Last Modified
July 10, 2026
Advisory Details (2)
Auto-updated Jul 8, 2026🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github Patch Available🟡 PoC Available
Quadratic-complexity (O(n^2)) DoS in js-yaml 5.x via !!omap tag in YAML11_SCHEMA · Advisory · nodeca/js-yaml · GitHub
https://github.com/nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvmgithub_commit
commit 39f3211a2f01 (nodeca/js-yaml)
Fix landed in nodeca/js-yaml commit 39f3211a2f01 — awaiting tagged release
https://github.com/nodeca/js-yaml/commit/39f3211a2f01b3c6982710cf21434ab7060acefeVendor Advisories for CVE-2026-59870(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(1)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| redhat | rust-main-1.96.1-1.hum1 | 2026-07-02 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(2)
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.
- 2026-07-11 15:26 UTCEG score recompute▲ 2.20
- 2026-07-11 15:26 UTCVendor advisory
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-10 20:19 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
- 2026-07-10 15:33 UTCEG score recompute
- 2026-07-10 15:33 UTCVendor advisory
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 15:40 UTCEG score recompute
- 2026-07-08 15:46 UTCEG score recompute
- 2026-07-08 15:45 UTCMITRE cvelistV5first tracked
Frequently asked(5)
What is CVE-2026-59870?
CVE-2026-59870 is a high vulnerability published on July 8, 2026. js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 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…
When was CVE-2026-59870 disclosed?
CVE-2026-59870 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-2026-59870 actively exploited?
CVE-2026-59870 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 21.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-59870?
CVE-2026-59870 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-59870?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59870, 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
Explore the affected products and dependency analysis for CVE-2026-59870
Is Your Infrastructure Affected by CVE-2026-59870?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.