CVE-2026-76833 @cgauge/yaml npm Package Arbitrary Code Execution via eval() YAML Tag
Attackers can execute arbitrary JavaScript by embedding malicious YAML tags, leading to full Node.js runtime compromise.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-76833?
CVE-2026-76833 is a high-severity code injection vulnerability in @cgauge/yaml, published on 20 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
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.
Weakness: CWE-95
Which versions are affected by CVE-2026-76833?
How do I fix CVE-2026-76833?
No fix has been published for CVE-2026-76833 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-76833 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-76833 exists.
Sources
Also known as GHSA-fqg3-vq72-r4q2.