CVE-2026-100721

CRITICALPre-NVD 9.09.0—
EchelonGraph scoreHIGH confidence

Score 9.0 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-27. A secondary CVSS source baseline 9.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
9.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 9.0Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

vm2 before 3.12.2 contains an authorization bypass in the NodeVM external-module resolver. When an embedder configures require.external with a custom resolver (and context: 'host'), LegacyResolver.customResolve in lib/resolver-compat.js records the resolved module directory in this.externals as new RegExp('^' + escapeRegExp(resolvedPath)), without requiring a path separator or end-of-string boundary. Untrusted guest code can therefore require the allowlisted module (e.g. foo) and then require the absolute path of a non-allowlisted sibling whose path merely shares the resolved prefix (e.g. .../node_modules/foo2/index.js); the sibling passes isPathAllowedForModule and is loaded through hostRequire, so its top-level code runs in the host process before the exports are wrapped with vm.readonly, resulting in a sandbox escape and arbitrary code execution in the host context.

CVSS v3
9.0
EG Score
9.0CRITICALhigh confidence
EG Risk
57
EG Risk 57/100CISA SSVC

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
Severity90% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
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
0.4%
EPSS %ILE
31st
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

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 no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 27, 2026

Last Modified

September 28, 2026

Advisory Details (5)

Auto-updated Sep 27, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit.
generic

vm2 before 3.12.2 Authorization Bypass via Custom Resolver | Advisories | VulnCheck

https://www.vulncheck.com/advisories/vm2-before-3.12.2-authorization-bypass-via-custom-resolver
github_commit Patch Available

commit 91034466bfb7 (patriksimek/vm2)

Patch available: patriksimek/vm2 v3.12.0 (contains commit 91034466bfb7)

https://github.com/patriksimek/vm2/commit/91034466bfb7f56b95fd48083ec6ca36d058f164
github_commit Patch Available

commit ab4ee7d803e8 (patriksimek/vm2)

Patch available: patriksimek/vm2 v3.11.7 (contains commit ab4ee7d803e8)

https://github.com/patriksimek/vm2/commit/ab4ee7d803e8c80155e9eb3672226bddbca4aa9c
github_commit Patch Available

commit 6ac3916da84e (patriksimek/vm2)

Patch available: patriksimek/vm2 v3.11.7 (contains commit 6ac3916da84e)

https://github.com/patriksimek/vm2/commit/6ac3916da84e060c403e407b6b6318fcc66b0e72
github Patch Available🟡 PoC Available

NodeVM custom resolution bypasses external path boundaries · Advisory · patriksimek/vm2 · GitHub

https://github.com/patriksimek/vm2/security/advisories/GHSA-5h3f-q97h-ccvc

Vendor Advisories for CVE-2026-100721(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 52× in last 7d / 58× 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. 2026-10-04 10:50 UTCGHSA enrichment
  2. 2026-10-04 06:24 UTCGHSA enrichment
  3. 2026-10-04 02:00 UTCGHSA enrichment
  4. 2026-10-03 21:37 UTCGHSA enrichment
  5. 2026-10-03 17:13 UTCEG score recompute
  6. 2026-10-03 17:13 UTCGHSA enrichment
  7. 2026-10-03 14:25 UTCEPSS rescore
  8. 2026-10-03 12:47 UTCGHSA enrichment
  9. 2026-10-03 08:23 UTCGHSA enrichment
  10. 2026-10-03 03:56 UTCGHSA enrichment
  11. 2026-10-02 23:28 UTCGHSA enrichment
  12. 2026-10-02 18:57 UTCEG score recompute
  13. 2026-10-02 18:57 UTCGHSA enrichment
  14. 2026-10-02 14:33 UTCGHSA enrichment
  15. 2026-10-02 09:55 UTCGHSA enrichment
  16. 2026-10-02 05:31 UTCGHSA enrichment
  17. 2026-10-02 01:07 UTCGHSA enrichment
  18. 2026-10-01 20:42 UTCEG score recompute
  19. 2026-10-01 20:42 UTCGHSA enrichment
  20. 2026-10-01 19:49 UTCEPSS rescore
  21. 2026-10-01 16:16 UTCGHSA enrichment
  22. 2026-10-01 11:53 UTCGHSA enrichment
  23. 2026-10-01 07:29 UTCGHSA enrichment
  24. 2026-10-01 03:05 UTCGHSA enrichment
  25. 2026-09-30 22:41 UTCGHSA enrichment
Show 33 more
  1. 2026-09-30 18:18 UTCEG score recompute
  2. 2026-09-30 18:18 UTCGHSA enrichment
  3. 2026-09-30 15:02 UTCEPSS rescore
  4. 2026-09-30 13:55 UTCGHSA enrichment
  5. 2026-09-30 09:30 UTCGHSA enrichment
  6. 2026-09-30 05:04 UTCGHSA enrichment
  7. 2026-09-30 00:40 UTCGHSA enrichment
  8. 2026-09-29 20:16 UTCGHSA enrichment
  9. 2026-09-29 15:49 UTCEG score recompute
  10. 2026-09-29 15:48 UTCGHSA enrichment
  11. 2026-09-29 15:20 UTCEPSS rescore
  12. 2026-09-29 11:19 UTCGHSA enrichment
  13. 2026-09-29 06:49 UTCGHSA enrichment
  14. 2026-09-29 02:26 UTCGHSA enrichment
  15. 2026-09-28 22:02 UTCEG score recompute
  16. 2026-09-28 22:02 UTCGHSA enrichment
  17. 2026-09-28 17:39 UTCEG score recompute
  18. 2026-09-28 17:38 UTCGHSA enrichment
  19. 2026-09-28 17:03 UTCEG score recompute
  20. 2026-09-28 17:02 UTCGHSA enrichment
  21. 2026-09-28 13:51 UTCGHSA enrichment
  22. 2026-09-28 09:27 UTCGHSA enrichment
  23. 2026-09-28 05:03 UTCGHSA enrichment
  24. 2026-09-28 00:40 UTCGHSA enrichment
  25. 2026-09-27 20:16 UTCGHSA enrichment
  26. 2026-09-27 15:52 UTCEG score recompute
  27. 2026-09-27 15:52 UTCGHSA enrichment
  28. 2026-09-27 11:26 UTCGHSA enrichment
  29. 2026-09-27 07:01 UTCEG score recompute
  30. 2026-09-27 07:01 UTCGHSA enrichment
  31. 2026-09-27 02:37 UTCEG score recompute
  32. 2026-09-27 01:53 UTCEG score recompute
  33. 2026-09-27 01:49 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-100721?
CVE-2026-100721 is a critical vulnerability published on September 27, 2026. vm2 before 3.12.2 contains an authorization bypass in the NodeVM external-module resolver. When an embedder configures require.external with a custom resolver (and context: 'host'), LegacyResolver.customResolve in lib/resolver-compat.js records the resolved module directory in this.externals as new…
When was CVE-2026-100721 disclosed?
CVE-2026-100721 was first published on September 27, 2026, with the most recent update on September 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-100721 actively exploited?
CVE-2026-100721 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (31st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-100721?
CVE-2026-100721 has a CVSS base score of 9.0 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-100721?
A fix for CVE-2026-100721 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-100721 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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