High · CVSS 7.8CVE-2026-76833

@cgauge/yaml npm Package Arbitrary Code Execution via eval() YAML TagCVE-2026-76833

Answer in brief

CVE-2026-76833 records a High severity (CVSS 7.8) vulnerability in @cgauge/yaml npm Package Arbitrary Code Execution via eval() YAML Tag. The current sources do not mark it as known exploited. The current feed maps cgauge/@cgauge/yaml (generic), cgauge/@cgauge/yaml (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 20, 2026Updated Sep 24, 2026Source checked Oct 4, 2026First seen by HOL Aug 20, 2026Material review Sep 24, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.8
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Not reported

Why this deserves its current priority

CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps cgauge/@cgauge/yaml (generic), cgauge/@cgauge/yaml (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
cgauge/@cgauge/yamlgeneric	0	Not reported
cgauge/@cgauge/yamlgeneric	*	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for cgauge/@cgauge/yaml, cgauge/@cgauge/yaml.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Aug 20, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 20, 2026

Sources and claim methodology

Upstream source description

@cgauge/yaml npm package contains an arbitrary code execution vulnerability that allows attackers to execute arbitrary JavaScript by embedding a custom !js YAML tag whose construct callback unconditionally calls eval() on attacker-supplied string values during document parsing. Any application parsing untrusted YAML input with this library exposes full Node.js runtime authority, including environment variable access, filesystem read/write, network access, and subprocess execution, with no safe-mode alternative or opt-out mechanism available.

Quoted source text, attributed separately from HOL analysis.