CVE-2026-24000: Github.com/fleetdm/fleet/v4 Fleet Has A Rate Limiting Vulnerability
MODERATECVE-2026-24000 is a MODERATE (CVSS 5.3) fleet has a rate limiting vulnerability (CWE-290: Authentication Bypass by Spoofing) affecting Github.com/fleetdm/fleet/v4 libraries in the Go ecosystem. The issue involves fleet has a rate limiting bypass via untrusted client ip headers. Remediation is available by upgrading affected packages to version 4.80.1.
CVE-2026-24000 at a Glance
Security Impact
CVSS: 5.3
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).
How to Fix CVE-2026-24000
To remediate this vulnerability, upgrade all affected Github.com/fleetdm/fleet/v4 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/fleetdm/fleet/v4 to 4.80.1Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/fleetdm/fleet/v4How to Check if You Are Affected
To determine whether your application is affected by CVE-2026-24000, inspect your project dependencies for Github.com/fleetdm/fleet/v4:
inspect dependencies for github.com/fleetdm/fleet/v4Analyze the terminal output to locate any version of Github.com/fleetdm/fleet/v4 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.80.1), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-290: Authentication Bypass by Spoofing, where this attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. In Github.com/fleetdm/fleet/v4, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-24000 Affected Github.com/fleetdm/fleet/v4 Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/fleetdm/fleet/v4
|
Go |
< 4.80.1
|
4.80.1
|
References
Frequently Asked Questions
What is CVE-2026-24000?
Which Github.com/fleetdm/fleet/v4 versions are affected?
What version fixes CVE-2026-24000?
Is github.com/fleetdm/fleet/v4 affected?
What is the CVSS score of CVE-2026-24000?
What CWE is associated with CVE-2026-24000?
How can I check Go dependencies for CVE-2026-24000?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-j8h8-75h3-jg53",
"modified" : "2026-05-15T23:44:40Z",
"published" : "2026-05-14T13:13:39Z",
"aliases" : [ "CVE-2026-24000" ],
"summary" : "Fleet has a rate limiting bypass via untrusted client IP headers",
"details" : "### Impact\n\nFleet 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.\n\nFleet determines a client’s public IP address using HTTP headers such as:\n- X-Forwarded-For\n- X-Real-IP\n- True-Client-IP\n\nThese 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.\n\nThis could allow an attacker to bypass per-IP rate limits and increase the effectiveness of brute-force or password-spraying attempts against authentication endpoints.\n\nThis issue does not allow authentication bypass, privilege escalation, data exposure, or remote code execution on its own.\n\n### Workarounds\n\nRun Fleet behind a trusted reverse proxy or load balancer that overwrites client IP headers.\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\nEmail us at [security@fleetdm.com](mailto:security@fleetdm.com)\nJoin #fleet in [osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw)\n\n### Credits\n\nWe thank @fuzzztf for responsibly reporting this issue.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
}, {
"type" : "CVSS_V4",
"score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/fleetdm/fleet/v4"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "4.80.1"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/fleetdm/fleet/security/advisories/GHSA-j8h8-75h3-jg53"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-24000"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/fleetdm/fleet"
}, {
"type" : "WEB",
"url" : "https://github.com/fleetdm/fleet/releases/tag/fleet-v4.80.1"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-290" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-05-14T13:13:39Z",
"nvd_published_at" : "2026-05-14T20:17:01Z"
}
}