CVE-2026-39911CWE-668

Hashgraph Guardian 3.5.1 Unsandboxed JavaScript Execution RCE

High · published April 9, 2026

CVSS v4.0
8.7
EPSS
1%
Percentile
55.7
In the wild
Unconfirmed
What it is

Hashgraph Guardian through version 3.5.1, fixed in commit 45fbe2f, contains an unsandboxed JavaScript execution vulnerability in the Custom Logic policy block worker that allows authenticated Standard Registry users to execute arbitrary code by passing user-supplied JavaScript expressions directly to the Node.js Function() constructor without isolation. Attackers can import native Node.js modules to read arbitrary files from the container filesystem, access process environment variables containing sensitive credentials such as RSA private keys, JWT signing keys, and API tokens, and forge valid authentication tokens for any user including administrators.

The record
Technical detail
CVSS v4.0
8.7 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
EPSS
0.00788 · 55.7th percentile
Weakness
CWE-668 · Exposure of Resource to Wrong Sphere
Published
2026-04-09T17:57Z
EPSS history
Timeline
  • 09 APR 17:57Z
    Hashgraph Guardian 3.5.1 Unsandboxed JavaScript Execution RCE
    cvelistv5