Incorrect Authorization in Fleet Server Leading to Denial of Service of Agent Upload Operations
Priority LOW 15CWE-863Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-863.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00295 22nd percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Elastic | Fleet Server | 8.0.0 – 8.19.15; 9.0.0 – 9.3.4; 9.4.0 – 9.4.1 | — | No fix listed | CNA |
- Fleet Server VendorElastic Affected 8.0.0 – 8.19.15; 9.0.0 – 9.3.4; 9.4.0 – 9.4.1 Fixed in — No fix listed CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:elastic:fleet_server:*:*:*:*:*:*:*:* | 8.0.0 to before 8.19.16; 9.0.0 to before 9.3.5; 9.4.0 to before 9.4.2 | Vulnerable | Elastic |
- cpe:2.3:a:elastic:fleet_server:*:*:*:*:*:*:*:* Versions 8.0.0 to before 8.19.16; 9.0.0 to before 9.3.5; 9.4.0 to before 9.4.2 Vulnerable ·Elastic
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-78587
- 2026-10-03 Alias added: GHSA-cg8q-4j53-92fq
References
More Elastic Fleet Server vulnerabilities
- TI-2023-25169 Fleet Server Insertion of Sensitive Information into Log File CVSS 3.1HIGH 8.1
- TI-2026-40526 Allocation of Resources Without Limits or Throttling in Fleet Server Leading to Denial of Service CVSS 3.1HIGH 7.5
- TI-2026-50895 Authorization Bypass Through User-Controlled Key in Fleet Server Leading to Information Disclosure CVSS 3.1MEDIUM 6.5
Sources
- CVE-2026-78587 · CVE Program
- CVE-2026-78587 · NVD
- FIRST EPSS
- GHSA-cg8q-4j53-92fq · GitHub Advisory Database · CC BY 4.0
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