CVE-2026-39911

Hashgraph Guardian 3.5.1 Unsandboxed JavaScript Execution RCE

State: Published
Severity: 8.7 High
Published: Apr 9, 2026
Updated: Jul 14, 2026
Reserved: Apr 7, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	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	VulnCheck
3.1	8.8 High	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	VulnCheck

Weaknesses

CWE-668 Exposure of Resource to Wrong Sphere

Affected Products

Product	Versions
guardianhashgraph	3.5.1 and earlierAffected 45fbe2f7e0e8feee30105d42d66ed63fb6177ebeNot affected

References

https://github.com/hashgraph/guardian/pull/5929issue-tracking
https://github.com/hashgraph/guardian/commit/45fbe2f7e0e8feee30105d42d66ed63fb6177ebepatch
https://www.vulncheck.com/advisories/hashgraph-guardian-unsandboxed-javascript-execution-rcethird-party-advisory

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