# 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. CVSS 3.1 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-78587
Last updated: 2026-09-03T19:11:53Z

- Published: 2026-09-02 14:43 UTC · Updated: 2026-09-03 19:11 UTC · Assigner: elastic
- CVSS: 3.1 (CVSS 3.1) · Severity: Low · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
- EPSS: 0.30%, 22th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-863

## 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.

## Affected vendors and products

- Elastic: Fleet Server

## Tracked companies

- [Elastic Cloud](https://rewindex.com/company/elastic-cloud.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-78587)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-78587)
- [https://discuss.elastic.co/t/fleet-server-8-19-16-9-3-5-9-4-2-security-update-esa-2026-164/390117](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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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-78587 · Markdown: https://rewindex.com/cve/CVE-2026-78587.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-78587 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:09:57.669Z