CVE-2026-78587 — Incorrect Authorization in Fleet Server Leading to Denial of Service of Agent Upload Operations

CVE-2026-78587

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

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
Elastic / Fleet Server	affected 8.0.0 through 8.19.15; affected 9.0.0 through 9.3.4; affected 9.4.0 through 9.4.1

CWE

CWE-863

References

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

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.