CVE-2026-126402 json
Fleet before 4.89.0 Broken Access Control via User Administration API
published 17d ago modified 2d ago also EUVD-2026-125163 , GHSA-mj9p-fq5h-mw8h
Unreviewed: the maintainers' own advisory
Published by the maintainers on their GitHub repository fleetdm/fleet. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.
- cvss
- 7.2
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 27%
- public exploits
- 0
- none known
Summary
Fleet before 4.89.0 contains an incorrect authorization flaw in its user administration API that accepts user creation or modification when the caller administers any one of the assigned teams. Authenticated team administrators can grant users administrator roles on other teams, then deploy software and execute scripts on those teams' hosts.
Patch / fix
- fleetdm fleet 4.89.0
Is CVE-2026-126402 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerExploit prediction
0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-14).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.6 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| CNA | 3.1 | 7.2 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
| CNA | 4.0 | 8.6 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 7.2 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
Affected products
- fleetdm fleet
Classification
- Weakness
-
- CWE-863 Incorrect Authorization
References
-
github.com
/fleetdm/fleet/security/advisories/GHSA-mj9p-fq5h-mw8h
vendor-advisory, advisory
-
vulncheck.com
/advisories/fleet-before-4.89.0-broken-access-control-via-user-administration-api
third-party-advisory
Sources
- CVE List CVE-2026-126402
- NVD CVE-2026-126402
- Maintainer advisory GHSA-mj9p-fq5h-mw8h
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
The maintainers of fleetdm/fleet published their own advisory on GitHub. Reviewed sources take precedence over it.