CVE-2026-102406 (CVSS 8.8)

Description

Authorization Bypass Through User-Controlled Key (CWE-639) in Kibana could lead to cross-tenant data interception. In this context, "tenant" refers to a user or team sharing the same Kibana deployment, not a separate Elastic Cloud organization or customer. Kibana's Fleet package installation process allowed a user holding delegated Fleet package-management privileges, without direct Elasticsearch administrative privileges, to claim a data stream identifier already in use by another tenant. Because ownership of that identifier was not verified before Fleet applied the uploaded package's generated index and ingest-pipeline settings to already-existing infrastructure, an attacker could redirect an existing tenant's data stream through infrastructure under their control. This exposed the affected tenant's subsequently ingested data to unauthorized disclosure and modification, and prevented that data from reaching its intended destination. Interception could continue even after the malicious package was removed, requiring separate remediation of the affected infrastructure.

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CVSS v3.1 Score

8.8

HIGH

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

EPSS — Exploit Prediction

0.0035

Probability of exploitation

0.27%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-639 CWE-639

References

Other References

https://discuss.elastic.co/t/kibana-8-19-22-9-4-7-9-5-4-security-update-esa-2026-187/390860

Frequently Asked Questions

What is CVE-2026-102406? +

Authorization Bypass Through User-Controlled Key (CWE-639) in Kibana could lead to cross-tenant data interception. In this context, "tenant" refers to a user or team sharing the same Kibana deployment, not a separate Elastic Cloud organization or customer. Kibana's Fleet package installation process allowed a user holding delegated Fleet package-management privileges, without direct Elasticsearch administrative privileges, to claim a data stream identifier already in use by another tenant. Because ownership of that identifier was not verified before Fleet applied the uploaded package's generated index and ingest-pipeline settings to already-existing infrastructure, an attacker could redirect an existing tenant's data stream through infrastructure under their control. This exposed the affected tenant's subsequently ingested data to unauthorized disclosure and modification, and prevented that data from reaching its intended destination. Interception could continue even after the malicious package was removed, requiring separate remediation of the affected infrastructure. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-102406? +

CVE-2026-102406 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0035, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-102406? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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