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FleetApplication · Fleetdm

CVE-2026-24000

MEDIUM · 5.3 CVSS v3.1 Published 2026-05-14
Fix available
A fix is available. Upgrade to 4.80.1 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

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. Prior to version 4.80.1, Fleet trusted client-supplied IP address headers when determining the source IP for incoming requests. This allowed authenticated and unauthenticated clients to spoof their apparent IP address and bypass per-IP rate limiting controls. Fleet determines a client’s public IP address using HTTP headers such as X-Forwarded-For, X-Real-IP, and/or True-Client-IP. These headers were trusted without validation. An attacker could supply arbitrary values in these headers, causing Fleet to treat each request as originating from a different IP address. This could allow an attacker to bypass per-IP rate limits and increase the effectiveness of brute-force or password-spraying attempts against authentication endpoints. This issue does not allow authentication bypass, privilege escalation, data exposure, or remote code execution on its own. Version 4.80.1 contains a patch. As a workaround, run Fleet behind a trusted reverse proxy or load balancer that overwrites client IP headers.

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 · high confidence

Fleet versions before 4.80.1 trusted client-supplied HTTP headers (X-Forwarded-For, X-Real-IP, True-Client-IP) without validation, allowing attackers to spoof their source IP address and bypass per-IP rate limiting controls.

MitigationDeploy Fleet behind a trusted reverse proxy or load balancer that overwrites client IP headers and prevents external clients from directly setting these headers, or upgrade to version 4.80.1 which validates the IP headers.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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:< 4.80.1

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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Fleet version
    Run 'fleet --version' or check the version displayed in the Fleet UI dashboard, or inspect the container/image tag if running via Docker/Kubernetes
    Affected if Version is below 4.80.1 (e.g., 4.80.0, 4.79.x, etc.)
  2. Determine if Fleet is exposed directly to the internet
    Review network architecture: check if Fleet listeners (ports 8080, 443) are exposed directly to untrusted clients or if a reverse proxy/load balancer sits in front
    Affected if Fleet is directly accessible to external clients without a trusted proxy layer
  3. Inspect proxy configuration for IP header handling
    Check the reverse proxy/load balancer configuration (e.g., nginx, HAProxy, AWS ALB) for settings that overwrite or strip X-Forwarded-For, X-Real-IP, and True-Client-IP headers from incoming requests
    Affected if The proxy is not configured to overwrite these headers or allow-list trusted sources, meaning clients can inject arbitrary IP values
  4. Verify IP rate limiting uses trusted sources
    Review Fleet rate limiting configuration and logs to confirm which IP source is being used for per-IP rate limiting checks
    Affected if Rate limiting relies on client-supplied headers without validation from a trusted proxy

You are affected if your Fleet version is below 4.80.1 AND external clients can directly set or influence the X-Forwarded-For, X-Real-IP, or True-Client-IP headers without a trusted proxy overwriting them.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 4.80.1 or later
Fixed in 4.80.1
Interim mitigation

Deploy Fleet behind a trusted reverse proxy or load balancer that overwrites client IP headers and prevents external clients from directly setting these headers, or upgrade to version 4.80.1 which validates the IP headers.

Recommended fix High confidence

Fleet 4.80.1

  1. Upgrade Fleet to version 4.80.1 or later to apply the patch that validates client-supplied IP headers
  2. If immediate upgrade is not possible, deploy Fleet behind a trusted reverse proxy or load balancer (such as Nginx, HAProxy, or AWS ALB) configured to overwrite X-Forwarded-For, X-Real-IP, and True-Client-IP headers with the actual client IP address from the proxy's perspective
  3. Configure the reverse proxy to set the X-Forwarded-For header based on the source IP of the incoming connection, discarding any client-supplied values
  4. Verify after upgrade or configuration change that Fleet correctly identifies the source IP by testing rate limiting behavior

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

Fix this in Fleet Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,980
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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-2026-24000 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data