How severe is CVE-2026-42399?

CVE-2026-42399 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-42399 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42399?

CVE-2026-42399 affects Elastic Kibana. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42399?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-42399 have an EU (EUVD) identifier?

Yes. CVE-2026-42399 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-33031.

When was CVE-2026-42399 published?

CVE-2026-42399 was published on 2026-05-28 and last updated on 2026-06-17.

CVE-2026-42399

CVE-2026-42399 is a medium-severity vulnerability in Elastic Kibana with a CVSS 3.x base score of 6.5. 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-400.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (21st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-33031
Weakness: CWE-400
Affected product: Elastic Kibana
Published: 2026-05-28
Last modified: 2026-06-17

Description

Uncontrolled Resource Consumption (CWE-400) in Kibana can lead to denial of service via Excessive Allocation (CAPEC-130). An authenticated low-privileged user can cause Kibana to consume exponentially increasing amounts of memory by submitting a specially crafted Timelion visualization expression containing deeply chained function calls. The resulting data structure grows without bound, exhausting available memory and causing the Kibana service to crash and become unavailable to all users.

Frequently asked questions

What is CVE-2026-42399?: Uncontrolled Resource Consumption (CWE-400) in Kibana can lead to denial of service via Excessive Allocation (CAPEC-130). An authenticated low-privileged user can cause Kibana to consume exponentially increasing amounts of memory by submitting a specially crafted Timelion visualization expression containing deeply chained function calls. The resulting data structure grows without bound, exhausting available memory and causing the Kibana service to crash and become unavailable to all users.
How severe is CVE-2026-42399?: CVE-2026-42399 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-42399 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42399?: CVE-2026-42399 affects Elastic Kibana. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42399?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-42399 have an EU (EUVD) identifier?: Yes. CVE-2026-42399 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-33031.
When was CVE-2026-42399 published?: CVE-2026-42399 was published on 2026-05-28 and last updated on 2026-06-17.

References

https://discuss.elastic.co/t/kibana-8-19-16-and-9-3-5-security-update-esa-2026-36/386556

Affected products (1)

cpe:2.3:a:elastic:kibana:*:*:*:*:*:*:*:*

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