RCE in Cgauge @Cgauge/yaml
CVE-2026-76833
@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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (11.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 11.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.001
Affected products
Weakness classification (CWE)
References
- github.com/cgauge/packages (product)
- gist.github.com/arjunjaincs/35da3a80b4b16f324f194acec18489ba (technical-description)
- www.vulncheck.com/advisories/cgauge-yaml-npm-package-arbitrary-code-execution-v… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-76833?
- CVE-2026-76833 is a high-severity vulnerability in Cgauge @Cgauge/yaml, classified under Eval Injection. CVSS score: 7.8/10. Published 2026-08-20.
- How severe is CVE-2026-76833?
- High severity. CVSS v3 base score is 7.8 out of 10.