CVE-2026-50029

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 86% 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
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: Elevated riskExposed: 0

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

js-toml is a TOML parser for JavaScript, Prior to version 1.1.2, the interpreter checks whether a key already exists in a parser-built container with if (object[key]) instead of if (key in object). When the prior value is a falsy primitive — false, 0, 0n, 0.0, -0, or "" — the duplicate-key branch is skipped and the value is silently overwritten by a later sub-table, dotted-key sub-table, or array-of-tables sharing the same name. Per the TOML 1.0.0 spec ("Defining a key multiple times is invalid"; "You cannot define any key or table more than once"), this should be a parse error. The result is structural type confusion of attacker-named keys in the value returned by load(). A boolean-typed false (or numeric 0) becomes a truthy object. Host applications that gate behavior on if (config.flag), if (!user.banned), if (config.allowDelete), or if (config.publicMode) will silently take the truthy branch. This is distinct from GHSA-65fc-cr5f-v7r2 (the 1.0.2 prototype-pollution fix). Object.prototype is not polluted. The Object.create(null) mitigation from 1.0.2 is intact; the bug here is in the duplicate-key state machine, not in container construction. Version 1.1.2 patches the incorrect comparison.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
55(Attend)
EG Risk 55/100SSVC: 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
Severity53% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
14%
KEV
Not listed

Published

June 26, 2026

Last Modified

August 17, 2026

Advisory Details (3)

Auto-updated Aug 14, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
github_release Patch Available

v1.1.2

Patch available: sunnyadn/js-toml v1.1.2

https://github.com/sunnyadn/js-toml/releases/tag/v1.1.2
github_commit Patch Available

commit e0504fa5d3dc (sunnyadn/js-toml)

Patch available: sunnyadn/js-toml v1.1.2 (contains commit e0504fa5d3dc)

https://github.com/sunnyadn/js-toml/commit/e0504fa5d3dcde2d1d588c9001c24b7b700beeeb
github Patch Available🟡 PoC Available

js-toml silent type confusion via falsy-primitive duplicate-key bypass · Advisory · sunnyadn/js-toml · GitHub

https://github.com/sunnyadn/js-toml/security/advisories/GHSA-m34p-749j-x6m6

Vendor Advisories for CVE-2026-50029(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-toml—1.1.2—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 21× 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 13:49 UTCEPSS rescore
  2. 2026-08-25 05:16 UTCEG score recompute
  3. 2026-08-23 07:51 UTCEG score recompute
  4. 2026-08-23 00:19 UTCEPSS rescore
  5. 2026-08-22 09:19 UTCEG score recompute
  6. 2026-08-21 23:49 UTCEPSS rescore
  7. 2026-08-21 04:59 UTCEG score recompute
  8. 2026-08-20 22:55 UTCEPSS rescore
  9. 2026-08-20 06:29 UTCEG score recompute
  10. 2026-08-19 17:04 UTCEPSS rescore
  11. 2026-08-18 23:29 UTCEG score recompute
  12. 2026-08-18 13:48 UTCEPSS rescore
  13. 2026-08-17 20:31 UTCEG score recompute
  14. 2026-08-17 19:40 UTCEG score recompute
  15. 2026-08-17 15:13 UTCEG score recompute
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-16 16:43 UTCEG score recompute
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 02:14 UTCEPSS rescore
  20. 2026-08-14 19:36 UTCEG score recompute
  21. 2026-07-30 13:18 UTCEG score recompute
  22. 2026-07-26 14:28 UTCEG score recompute
  23. 2026-07-23 03:18 UTCEG score recompute
  24. 2026-06-26 23:38 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-50029?
CVE-2026-50029 is a medium vulnerability published on June 26, 2026. js-toml is a TOML parser for JavaScript, Prior to version 1.1.2, the interpreter checks whether a key already exists in a parser-built container with if (object[key]) instead of if (key in object). When the prior value is a falsy primitive — false, 0, 0n, 0.0, -0, or "" — the duplicate-key branch…
When was CVE-2026-50029 disclosed?
CVE-2026-50029 was first published in the National Vulnerability Database on June 26, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-50029 actively exploited?
CVE-2026-50029 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 86.1% of all scored CVEs.
What is the CVSS score of CVE-2026-50029?
CVE-2026-50029 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-50029?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-50029, 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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