js-toml is a TOML parser for JavaScript. Prior to 1.1.3, load() does not bound nesting or dotted-key depth in the recursive parser at src/load/parser.ts or the interpreter at src/load/interpreter.ts, so deeply nested arrays, deeply nested inline tables, or long dotted keys can exhaust the V8 call stack and throw a raw RangeError instead of the documented SyntaxParseError. Applications that parse attacker-controlled TOML and handle only SyntaxParseError can rethrow the unexpected exception, which can terminate a worker or process and cause denial of service. The exception is synchronous and catchable by consumers that handle all exceptions, and the issue does not affect confidentiality or integrity. This issue is fixed in version 1.1.3.
CVE-2026-63386
MEDIUMPre-NVD 5.35.3Trending — 3 sources updated this week
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: secondary
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 5.3Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.3
- EG Score
- 5.3(low)
- EG Risk
- 28(Track)EG Risk 28/100SSVC: Track
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 computedSeverity53% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 1%
- EPSS %ILE
- 42%
- KEV
- Not listed
Published
September 22, 2026
Last Modified
September 23, 2026
Advisory Details (2)
Auto-updated Sep 22, 2026🔬 Proof of concept available. Patch available. Sources: github, github_commit.
github_commit Patch Available
commit 4e10acf1f99f (sunnyadn/js-toml)
Patch available: sunnyadn/js-toml v1.2.0 (contains commit 4e10acf1f99f)
https://github.com/sunnyadn/js-toml/commit/4e10acf1f99ff3cb443c58b8f0a57664e41e87c6github Patch Available🟡 PoC Available
Uncontrolled recursion in `load()` causes `RangeError` (stack exhaustion) on deeply nested input · Advisory · sunnyadn/js-toml · GitHub
https://github.com/sunnyadn/js-toml/security/advisories/GHSA-3g82-77xr-68x5Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 4× in last 7d / 4× 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.
- 2026-09-23 17:54 UTCEPSS rescore
- 2026-09-22 19:37 UTCEG score recompute
- 2026-09-22 19:08 UTCEG score recompute
- 2026-09-22 19:08 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-63386?
CVE-2026-63386 is a medium vulnerability published on September 22, 2026. js-toml is a TOML parser for JavaScript. Prior to 1.1.3, load() does not bound nesting or dotted-key depth in the recursive parser at src/load/parser.ts or the interpreter at src/load/interpreter.ts, so deeply nested arrays, deeply nested inline tables, or long dotted keys can exhaust the V8 call…
When was CVE-2026-63386 disclosed?
CVE-2026-63386 was first published in the National Vulnerability Database on September 22, 2026, with the most recent update on September 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63386 actively exploited?
CVE-2026-63386 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 57.7% of all scored CVEs.
What is the CVSS score of CVE-2026-63386?
CVE-2026-63386 has a CVSS v3 base score of 5.3 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-63386?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63386, 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-2026-63386
Is Your Infrastructure Affected by CVE-2026-63386?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.