CVE-2026-23517
CVE-2026-23517 is a CWE-862 vulnerability in github.com/fleetdm/fleet. O3 Security confirms whether CVE-2026-23517 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Fleet has an Access Control vulnerability in debug/pprof endpoints
Blast Radius
github.com/fleetdm/fleet🐹github.com/fleetdm/fleet🐹github.com/fleetdm/fleet🐹github.com/fleetdm/fleet🐹github.com/fleetdm/fleet/v4Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/fleetdm/fleet | ≥ 4.78.0&&< 4.78.3 | 4.78.3 |
| 🐹Go | github.com/fleetdm/fleet | ≥ 4.77.0&&< 4.77.1 | 4.77.1 |
| 🐹Go | github.com/fleetdm/fleet | ≥ 4.76.0&&< 4.76.2 | 4.76.2 |
| 🐹Go | github.com/fleetdm/fleet | ≥ 4.75.0&&< 4.75.2 | 4.75.2 |
| 🐹Go | github.com/fleetdm/fleet/v4 | all versions | 4.78.3-0.20260112221730-5c030e32a3a9 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/fleetdm/fleet. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/fleetdm/fleet to 4.78.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-23517 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-23517 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-23517. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-23517 in your dependencies?
O3 detects CVE-2026-23517 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.