CVE-2026-73643

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: 0.3%, 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
Elevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: Elevated riskExposed: 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 5.0.0 until 5.2.2, parsing a small YAML document can take exponential time when an application calls load() or loadAll() on untrusted input. In src/parser/parser.ts, readFlowCollection uses restoreState and calls parseNode a second time when a flow-sequence entry is recognized as a key: value pair. If the key is a nested flow sequence of the same shape, every level is parsed twice, causing O(2^n) work and allowing an input under 200 bytes to keep one CPU busy for minutes, block the Node.js event loop, and stall the process. No anchors, aliases, merges, tags, or nondefault options are required. This issue is fixed in version 5.2.2.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
27%
KEV
Not listed

Published

July 24, 2026

Last Modified

August 14, 2026

Advisory Details (2)

Auto-updated Aug 13, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github Patch Available🟡 PoC Available

Exponential parsing time in js-yaml flow collections leads to denial of service · Advisory · nodeca/js-yaml · GitHub

https://github.com/nodeca/js-yaml/security/advisories/GHSA-pm4m-ph32-ghv5
github_commit

commit 3e5240f9cbe6 (nodeca/js-yaml)

Fix landed in nodeca/js-yaml commit 3e5240f9cbe6 — awaiting tagged release

https://github.com/nodeca/js-yaml/commit/3e5240f9cbe645ce5afb58524954a13c8539c853

Vendor Advisories for CVE-2026-73643(1)

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

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
js-yaml—5.2.2—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 27× 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. 2026-08-25 19:11 UTCEG score recompute
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-24 18:05 UTCEG score recompute
  4. 2026-08-23 03:31 UTCEG score recompute
  5. 2026-08-23 00:19 UTCEPSS rescore
  6. 2026-08-22 02:29 UTCEG score recompute
  7. 2026-08-21 23:49 UTCEPSS rescore
  8. 2026-08-21 00:52 UTCEG score recompute
  9. 2026-08-20 22:56 UTCEPSS rescore
  10. 2026-08-19 23:51 UTCEG score recompute
  11. 2026-08-19 17:04 UTCEPSS rescore
  12. 2026-08-18 22:49 UTCEG score recompute
  13. 2026-08-18 13:49 UTCEPSS rescore
  14. 2026-08-18 13:49 UTCEPSS rescore
  15. 2026-08-17 21:37 UTCEG score recompute
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-16 20:36 UTCEG score recompute
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 14:56 UTCEPSS rescore
  20. 2026-08-16 08:05 UTCEG score recompute
  21. 2026-08-16 02:15 UTCEPSS rescore
  22. 2026-08-15 07:04 UTCEG score recompute
  23. 2026-08-15 01:31 UTCEPSS rescore
  24. 2026-08-14 17:36 UTCEG score recompute
  25. 2026-08-14 17:12 UTCEG score recompute
Show 2 more
  1. 2026-08-13 18:19 UTCEG score recompute
  2. 2026-08-13 17:52 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-73643?
CVE-2026-73643 is a high vulnerability published on July 24, 2026. js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 until 5.2.2, parsing a small YAML document can take exponential time when an application calls load() or loadAll() on untrusted input. In src/parser/parser.ts, readFlowCollection uses restoreState and calls parseNode a second time when a…
When was CVE-2026-73643 disclosed?
CVE-2026-73643 was first published in the National Vulnerability Database on July 24, 2026, with the most recent update on August 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-73643 actively exploited?
CVE-2026-73643 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 73.1% of all scored CVEs.
What is the CVSS score of CVE-2026-73643?
CVE-2026-73643 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-73643?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-73643, 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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