CVE-2026-39911

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.

CVSS 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

8.8CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

0.5% chance of exploitation in the next 30 days; higher than 45% of CVEs (scores of 2026-10-26)

CWE

CWE-668

Published

2026-04-09

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Affected

• hedera:guardian

References

• https://github.com/hashgraph/guardian/commit/45fbe2f7e0e8feee30105d42d66ed63fb6177ebe
• https://github.com/hashgraph/guardian/pull/5929
• https://www.vulncheck.com/advisories/hashgraph-guardian-unsandboxed-javascript-execution-rce

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