CVE-2026-24000: Fleet Device Management rate limiting bypass via IP spoofing

CVE-2026-24000 · Severity: medium · CVSS 5.3 · Published 2026-05-14

Fleet, an open-source device management platform, is vulnerable to a rate-limiting bypass. Attackers can spoof their source IP address by providing fake information in standard web headers, allowing them to circumvent security protections designed to block repeated login attempts. This increases the risk of successful brute-force or password-spraying attacks against user accounts.

Technologies: github.com/fleetdm/fleet/v4 (Go). Vendors: Go.

Quick answers

Is CVE-2026-24000 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-24000 being exploited in the wild.
How severe is CVE-2026-24000?
Medium severity, with a CVSS score of 5.3, published 14 May 2026.
Which products and versions are affected?
github.com/fleetdm/fleet/v4 (Go) < 4.80.1, SEMVER:introduced=0,fixed=4.80.1.
Is there a fix for CVE-2026-24000?
Yes. github.com/fleetdm/fleet/v4 (Go): upgrade to 4.80.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-24000 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-24000?
Check whether you run github.com/fleetdm/fleet/v4 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/fleetdm/fleet/v4 (Go): upgrade to 4.80.1 or later
    go get github.com/fleetdm/fleet/v4@v4.80.1

Technical details

Fleet fails to validate client-supplied HTTP headers (X-Forwarded-For, X-Real-IP, and True-Client-IP) when determining the source IP address for incoming requests. An unauthenticated remote attacker can supply arbitrary values in these headers to make each request appear as if it originates from a unique IP address. This effectively bypasses per-IP rate limiting mechanisms, facilitating large-scale brute-force or password-spraying attacks against authentication endpoints. The vulnerability is addressed in version 4.80.1, which introduces the FLEET_SERVER_TRUSTED_PROXIES configuration to properly handle proxy headers.

Affected products

  • Fleet Device Management (fleetdm) Fleet < 4.80.1

Identifiers

  • CVE-2026-24000
  • GHSA-j8h8-75h3-jg53
  • GO-2026-5455

Timeline

  • 2026-02-06: patched: Version 4.80.1 released
  • 2026-05-13: disclosed: Initial advisory publication
  • 2026-05-14: advisory: GitHub Advisory and CVE published

References

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