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
“—” beside the score: it is equal to NVD's CVSS score.
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.7% (54th percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 5.3 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2026-07-20) is not newer than that change (2026-10-25), so it does not.
Also known asEUVD-2026-42300 (ENISA EUVD) · GHSA-724g-mxrg-4qvm (GitHub Security Advisories)Source: ENISA EUVD
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5HIGHmedium confidence
- EG Risk
- 65EG Risk 65/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity75% × 45%Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.7%
- EPSS %ILE
- 54th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 0.7% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
July 8, 2026
Last Modified
October 25, 2026
Advisory Details (2)
Auto-updated Jul 8, 2026Quadratic-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-4qvmcommit 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(9)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- GHSA-724g-mxrg-4qvmGitHub Security AdvisoriesMedium
js-yaml: Quadratic-complexity (O(n^2)) DoS via !!omap tag in YAML11_SCHEMA
- RHSA-2026:35272Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:34975Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:34478Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
- RHSA-2026:33866Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
- RHSA-2026:26994Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:9455Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:7655Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- +1 more
Patch Availability(9)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| redhat | nodejs22-main-22.23.1-2.hum1 | 2026-07-03 | redhat |
| redhat | rust-main-1.96.1-1.hum1 | 2026-07-02 | redhat |
| redhat | nodejs24-main-24.18.0-0.2.hum1 | 2026-07-01 | redhat |
| redhat | nodejs26-main-26.4.0-1.3.hum1 | 2026-06-30 | redhat |
| redhat | dotnet8-0-main-8.0.128-1.hum1 | 2026-06-18 | redhat |
| redhat | nodejs20-main-20.20.2-1.hum1 | 2026-04-21 | redhat |
| redhat | yarnpkg-main-1.22.22-18.1.hum1 | 2026-04-11 | redhat |
| redhat | nodejs25-main-25.9.0-1.1.hum1 | 2026-04-10 | redhat |
| npm | js-yaml @ 5.2.1 (fixes >= 5.0.0, <= 5.2.0) | — | ghsa |
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.
Affected Packages
(1 across 1 ecosystem)
npm(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| js-yaml | — |
| — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 12× in last 7d / 48× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 100 of 268 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 168 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-01 18:17 UTCEG score recompute
- 2026-11-01 18:17 UTCVendor advisory
- 2026-11-01 18:17 UTCGHSA enrichmentGHSA-724g-mxrg-4qvm · GitHub severity MODERATE · GitHub CVSS 5.3
- 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-11-01 07:42 UTCGHSA enrichmentGHSA-724g-mxrg-4qvm · GitHub severity MODERATE · GitHub CVSS 5.3
- 2026-11-01 07:42 UTCEG score recompute
- 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-10-25 20:26 UTCEG score recompute
- 2026-10-25 20:26 UTCVendor advisory
- 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-10-25 14:16 UTCEG score recompute
- 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.7% · 54th percentile
- 2026-10-20 18:57 UTCEG score recompute
- 2026-10-20 18:57 UTCVendor advisory
- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-18 03:27 UTCEG score recompute
Show 75 moreShow fewer
- 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-13 15:48 UTCEG score recompute
- 2026-10-13 15:48 UTCVendor advisory
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-12 15:52 UTCEG score recompute
- 2026-10-11 19:36 UTCEG score recompute
- 2026-10-11 16:51 UTCEG score recompute
- 2026-10-11 14:13 UTCEG score recompute
- 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
- 2026-10-06 16:21 UTCVendor advisory
- 2026-10-06 15:38 UTCEG score recompute
- 2026-10-06 15:38 UTCVendor advisory
- 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-01 16:12 UTCEG score recompute
- 2026-10-01 16:12 UTCVendor advisory
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-28 13:23 UTCEG score recompute
- 2026-09-28 13:23 UTCVendor advisory
- 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-24 11:52 UTCEG score recompute
- 2026-09-24 11:52 UTCVendor advisory
- 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-09-23 06:11 UTCEG score recompute
- 2026-09-23 06:11 UTCVendor advisory
- 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-09-18 05:45 UTCEG score recompute
- 2026-09-18 05:45 UTCVendor advisory
- 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-13 23:50 UTCEG score recompute
- 2026-09-13 23:50 UTCVendor advisory
- 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-13 08:25 UTCVendor advisory
- 2026-09-12 16:42 UTCEG score recompute
- 2026-09-12 16:42 UTCVendor advisory
- 2026-09-12 03:35 UTCEG score recompute
- 2026-09-12 03:35 UTCVendor advisory
- 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-06 14:04 UTCEG score recompute
- 2026-09-06 14:04 UTCVendor advisory
- 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-05 22:49 UTCEG score recompute
- 2026-09-05 22:49 UTCVendor advisory
- 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-08-30 20:25 UTCEG score recompute
- 2026-08-30 20:25 UTCVendor advisory
- 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-08-30 07:37 UTCEG score recompute
- 2026-08-30 07:37 UTCVendor advisory
- 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.6% · 48th percentile
Related CVEs(same product + same vendor + same CWE)
Same product
7 shownnpm:js-yaml
Same vendor
10 shownredhat:RHSA-2026:26994 · redhat:RHSA-2026:33866 · redhat:RHSA-2026:7378
Frequently asked(5)
What is CVE-2026-59870?
When was the CVE record for CVE-2026-59870 published?
Is CVE-2026-59870 actively exploited?
What is the CVSS score of CVE-2026-59870?
How do I remediate CVE-2026-59870?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by 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.