FleetApplication · Fleetdm

CVE-2026-23517

HIGH · 8.1 CVSS v3.1 Published 2026-01-21
Fix available
A fix is available. Upgrade to 4.53.3 / 4.75.2 or later.
See remediation →
87/100
Remediation priority · High
Remotely reachable Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-862

The application checks who you are but not whether you're allowed to perform a given action, so any authenticated user can reach things meant for others. This is the classic “change the ID in the URL” bug. The fix is an authorization check on every request, evaluated against the acting user's permissions.

General guidance for the missing authorization class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FleetApplication
Affected:< 4.53.3>= 4.75.0, < 4.75.2>= 4.76.0, < 4.76.2>= 4.78.0, < 4.78.3= 4.77.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.53.3 / 4.75.2 / 4.76.2 or later
Fixed in 4.53.34.75.24.76.2
Vendor patch github.com →
Recommended fix High confidence

4.78.3 (or the latest 4.x stable release)

  1. 1. Identify your current Fleet version using `fleetctl --version` or checking the Fleet UI
  2. 2. Determine the appropriate upgrade path based on your current version: if < 4.53.3, upgrade to 4.53.3 minimum; if >= 4.75.0 and < 4.75.2, upgrade to 4.75.2 or higher; if >= 4.76.0 and < 4.76.2, upgrade to 4.76.2 or higher; if >= 4.78.0 and < 4.78.3, upgrade to 4.78.3
  3. 3. For self-managed deployments: upgrade Fleet server using your deployment method (e.g., Kubernetes Helm chart, Docker, or package manager) to the appropriate fixed version
  4. 4. If using Fleet DM cloud: verify that your managed instance has been updated by Fleet
  5. 5. After upgrade, verify that debug/pprof endpoints are no longer accessible to low-privilege Observer role users
  6. 6. As an additional mitigation (if immediate upgrade is not possible): configure your reverse proxy or load balancer to put debug/pprof endpoints (typically /debug/pprof/*) behind an IP allowlist restricted to trusted administrative IPs only
Caveat Review release notes for any breaking changes between your current version and target version before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,950. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-23517 in production — separate from our analysis above.

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