CVE-2026-39911 HIGH

CVE-2026-39911: Hashgraph Guardian 3.5.1 Unsandboxed JavaScript Execution RCE

Vendor Hashgraph
Product guardian
Weakness CWE-668
Published April 9, 2026
Last update May 1, 2026

CVSS base score

8.7/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS 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

What the vulnerability does

Description

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.

Key dates

Disclosure timeline

April 9, 2026 CVE published
May 1, 2026 Record updated