How severe is CVE-2026-39816?

CVE-2026-39816 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-2026-39816 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39816?

CVE-2026-39816 affects Apache Nifi. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-39816?

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-2026-39816 have an EU (EUVD) identifier?

Yes. CVE-2026-39816 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28593.

When was CVE-2026-39816 published?

CVE-2026-39816 was published on 2026-05-08 and last updated on 2026-06-17.

CVE-2026-39816

CVE-2026-39816 is a high-severity vulnerability in Apache Nifi 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-862.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v4: 7.5
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-28593
Weakness: CWE-862
Affected product: Apache Nifi
Published: 2026-05-08
Last modified: 2026-06-17

Description

The optional extension component TinkerpopClientService is missing the Restricted annotation with the Execute Code Required Permission in Apache NiFi 2.0.0-M1 through 2.8.0. The TinkerpopClientService supports configuration of ByteCode Submission for the Script Submission Type, enabling Groovy Script execution in the service prior to submitting the query. The missing Restricted annotation allows users without the Execute Code Permission to configure the Service in installations that use fine-grained authorization and have the optional TinkerpopClientService installed. Apache NiFi installations that do not have the nifi-other-graph-services-nar installed are not subject to this vulnerability. Upgrading to Apache NiFi 2.9.0 is the recommended mitigation.

Frequently asked questions

What is CVE-2026-39816?: The optional extension component TinkerpopClientService is missing the Restricted annotation with the Execute Code Required Permission in Apache NiFi 2.0.0-M1 through 2.8.0. The TinkerpopClientService supports configuration of ByteCode Submission for the Script Submission Type, enabling Groovy Script execution in the service prior to submitting the query. The missing Restricted annotation allows users without the Execute Code Permission to configure the Service in installations that use fine-grained authorization and have the optional TinkerpopClientService installed. Apache NiFi installations that do not have the nifi-other-graph-services-nar installed are not subject to this vulnerability. Upgrading to Apache NiFi 2.9.0 is the recommended mitigation.
How severe is CVE-2026-39816?: CVE-2026-39816 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-2026-39816 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39816?: CVE-2026-39816 affects Apache Nifi. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39816?: 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-2026-39816 have an EU (EUVD) identifier?: Yes. CVE-2026-39816 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28593.
When was CVE-2026-39816 published?: CVE-2026-39816 was published on 2026-05-08 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apache:nifi:*:*:*:*:*:*:*:*

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