Uncovered JavaScript Execution Flaw in Hashgraph Guardian Product by Hashgraph
CVE-2026-39911

8.7HIGH

Key Information:

Vendor

Hashgraph

Status
Guardian
Vendor
CVE Published:
9 April 2026

What is CVE-2026-39911?

Hashgraph Guardian through version 3.5.0 is susceptible to a serious unsandboxed JavaScript execution vulnerability within the Custom Logic policy block worker. This flaw allows authenticated users to execute arbitrary code by sending user-defined JavaScript expressions directly to the Node.js Function() constructor without proper isolation. By exploiting this vulnerability, attackers can utilize native Node.js modules to access arbitrary files in the container's filesystem and retrieve sensitive process environment variables, including RSA private keys, JWT signing keys, and API tokens. Furthermore, the vulnerability can enable an attacker to forge valid authentication tokens, potentially compromising any user account, including those of administrators.

Affected Version(s)

guardian 0 <= 3.5.0

References

https://github.com/hashgraph/guardian/pull/5929
issue-trackingmitigation
https://www.vulncheck.com/advisories/hashgraph-guardian-u...
third-party-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Christ Bouchuen
.