Vulnerability · Published Sep 2, 2026 · Assigned by elastic
CVE-2026-78587Incorrect Authorization in Fleet Server Leading to Denial of Service of Agent Upload Operations
Low 3.1
In plain English
A low-severity incorrect authorization in Fleet Server from Elastic. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities).
Severity (CVSS 3.1)3.1Low
Exploit odds (30 days)0.3%top 77.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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 products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Elastic | Fleet Server | 8.0.0 – through 8.19.159.0.0 – through 9.3.49.4.0 – through 9.4.1 |
Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L