CVE-2026-78587

Incorrect Authorization in Fleet Server Leading to Denial of Service of Agent Upload Operations

State: Published
Severity: 3.1 Low
Published: Sep 2, 2026
Updated: Sep 2, 2026
Reserved: Aug 24, 2026

Description

Incorrect Authorization (CWE-863) in Fleet Server can lead to a denial of service of agent upload operations via Privilege Abuse (CAPEC-122). Fleet Server does not correctly verify session ownership during multi-part data upload operations, allowing any authenticated agent to interfere with the active upload sessions belonging to other enrolled agents.

Scores

CVSS	Score	Vector	Source
3.1	3.1 Low	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L	elastic

Weaknesses

CWE-863 Incorrect Authorization

Affected Products

Product	Versions
Fleet ServerElastic	8.0.0 through 8.19.15Affected 9.0.0 through 9.3.4Affected 9.4.0 through 9.4.1Affected

References

https://discuss.elastic.co/t/fleet-server-8-19-16-9-3-5-9-4-2-security-update-esa-2026-164/390117

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