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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-78587
StatePUBLISHED
Assignerelastic
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-02 15:17:40 UTC
Updated2026-09-03 19:11:53 UTC
DescriptionIncorrect 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.

Risk And Classification

Primary CVSS: v3.1 3.1 LOW from [email protected]

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

EPSS: 0.002030000 probability, percentile 0.102370000 (date 2026-09-04)

Problem Types: CWE-863 | CWE-863 CWE-863 Incorrect Authorization

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary3.1LOWCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
3.1CNACVSS3.1LOWCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Elastic Fleet Server All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Elastic Fleet Server affected 8.0.0 8.19.15 semver Not specified
CNA Elastic Fleet Server affected 9.0.0 9.3.4 semver Not specified
CNA Elastic Fleet Server affected 9.4.0 9.4.1 semver Not specified

References

ReferenceSourceLinkTags
discuss.elastic.co/t/fleet-server-8-19-16-9-3-5-9-4-2-security-update-esa-2026-1... [email protected] discuss.elastic.co Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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