3.1

CVE-2026-78587: elastic fleet_server Incorrect Authorization

CVSS: 3.1v3.1LowAnalyzed
Published 02-09-2026Last modified 02-09-2026
Open JSON

Vulnerability summary

CVE-2026-78587 is a low (CVSS 3.1) Incorrect Authorization vulnerability in elastic fleet_server. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 20.6% of scored vulnerabilities.

Overall risk
12/100
0100
Low · default modelHow is this calculated?
CVSS score
3.1/10
010
Low · v3.1 (CVE.org)
EPSS score
0.29%
0%100%
Low · +0.07 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 02-09-2026
    PublishedVulnerability first disclosed.
  2. 02-09-2026
    Last modifiedVulnerability information updated.

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 metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.29%

Chance of exploitation in the next 30 days

Percentile

21%

Versus all other CVEs

30-day change

+0.07 pp

From 0.23% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.29%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Elastic1 product
  • fleet_server≥ 8.0.0, ≤ 8.19.15 | ≥ 9.0.0, ≤ 9.3.4 | ≥ 9.4.0, ≤ 9.4.1 | ≥ 8.0.0, < 8.19.16 | ≥ 9.0.0, < 9.3.5 | ≥ 9.4.0, < 9.4.2

1 vendor · 1 product

References

1 links