How severe is CVE-2026-39911?

CVE-2026-39911 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-39911 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39911?

CVE-2026-39911 affects Hedera Guardian. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-39911?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-39911 have an EU (EUVD) identifier?

Yes. CVE-2026-39911 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20993.

When was CVE-2026-39911 published?

CVE-2026-39911 was published on 2026-04-09 and last updated on 2026-06-17.

CVE-2026-39911

CVE-2026-39911 is a high-severity vulnerability in Hedera Guardian with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-668.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v4: 8.7
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-20993
Weakness: CWE-668
Affected product: Hedera Guardian
Published: 2026-04-09
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-39911?: CVE-2026-39911 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-39911 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39911?: CVE-2026-39911 affects Hedera Guardian. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39911?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-39911 have an EU (EUVD) identifier?: Yes. CVE-2026-39911 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20993.
When was CVE-2026-39911 published?: CVE-2026-39911 was published on 2026-04-09 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:hedera:guardian:*:*:*:*:*:*:*:*

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