CVE-2026-78587: CWE-863 Incorrect Authorization in Elastic Fleet Server
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.
CVSS v3.1
Score 3.1low
Affected software
Elastic
Fleet Server
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CWE-863) in Elastic Fleet Server involves improper authorization checks during multi-part data upload operations. Authenticated agents can abuse privileges to disrupt active upload sessions of other enrolled agents, leading to denial of service conditions. The issue is due to Fleet Server failing to verify session ownership correctly. No known exploits are reported in the wild. The affected versions explicitly include 8.0.0, 9.0.0, and 9.4.0. There is no vendor advisory or patch information provided, and the remediation level is not stated.
Potential Impact
The impact is limited to denial of service (availability) of agent upload operations. There is no impact on confidentiality or integrity. The vulnerability requires authenticated agents and has a high attack complexity, resulting in a low overall severity score (CVSS 3.1). No known active exploitation has been reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict agent authentication to trusted entities and monitor for unusual upload session interference. Follow vendor updates for official patches or workarounds.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- elastic
- Date Reserved
- 2026-08-24T21:13:45.972Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a983847acd9273b495d15d0
Added to database: 09/02/2026, 14:52:55 UTC
Last enriched: 09/07/2026, 13:43:35 UTC
Last updated: 10/16/2026, 06:48:19 UTC
Views: 66
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.