Vulnerability · Published Aug 20, 2026 · Assigned by VulnCheck

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

High 7.8

In plain English

A high-severity security flaw in @cgauge/yaml from cgauge. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities).

Severity (CVSS 3.1)7.8High

Exploit odds (30 days)0.2%top 87.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
cgauge	@cgauge/yaml	0 – through 0.27.0

Weakness: CWE-95 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References

GitHub Repository product
GitHub GIST technical-description
https://www.vulncheck.com/advisories/cgauge-yaml-npm-package-arbitrary-code-execution-via-eval-yaml-tag third-party-advisory