CVE-2026-39911Network attack vector

Authenticated code execution via unsandboxed Function constructor

Published Apr 9, 2026 · Updated Apr 9, 2026

Unsandboxed JavaScript execution in Guardian 3.5.1 and earlier allows remote authenticated users to execute arbitrary code. The Custom Logic policy worker passes user-supplied expressions to the Node.js Function() constructor in the policy-service context, exposing the full runtime without isolation. Standard Registry access is required; successful execution can read container files and environment secrets and forge administrator authentication tokens.

CVSS severity8.7
High
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsandboxed JavaScript execution in Guardian 3.5.1 and earlier allows remote authenticated users to execute arbitrary code. The Custom Logic policy worker passes user-supplied expressions to the Node.js Function() constructor in the policy-service context, exposing the full runtime without isolation. Standard Registry access is required; successful execution can read container files and environment secrets and forge administrator authentication tokens.

The record

CVE
CVE-2026-39911
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
Hedera Hashgraph
Product
Guardian
Classifications
CWE-668, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=3.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Hedera Hashgraph · Guardianversion=0 <=3.5.0

Published CVSS scores

8.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.7VulnCheckCVSS: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 describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-668Exposure of Resource to Wrong Sphere
T1059.007JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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