Auth bypass in Fleetdm Fleet

CVE-2026-23517

Fleet is open source device management software. A broken access control issue in versions prior to 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3 allowed authenticated users to access debug and profiling endpoints regardless of role. As a result, low-privilege users could view internal server diagnostics and trigger resource-intensive profiling operations. Fleet’s debug/pprof endpoints are accessible to any authenticated user regardless of role, including the lowest-privilege “Observer” role. This allows low-privilege users to access sensitive server internals, including runtime profiling data and in-memory application state, and to trigger CPU-intensive profiling operations that could lead to denial of service. Versions 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3 fix the issue. If an immediate upgrade is not possible, users should put the debug/pprof endpoints behind an IP allowlist as a workaround.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H.

EPSS exploit prediction

EPSS: 0.003 (20.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-23517: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000

Affected products

  • Fleetdm Fleet — versions >= 4.75.0, < 4.75.2, >= 4.77.0, < 4.77.1, >= 4.78.0, < 4.78.3

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-23517?
CVE-2026-23517 is a high-severity vulnerability in Fleetdm Fleet, classified under Missing Authorization. CVSS score: 8.1/10. Published 2026-01-21.
How severe is CVE-2026-23517?
High severity. CVSS v3 base score is 8.1 out of 10.