CVE-2026-24000

Fleet has a rate limiting bypass via untrusted client IP headers

MEDIUM
5.3
CVSS Score
Published: May 14, 2026 at 06:56 PM UTC
Updated: October 26, 2026 at 02:10 PM UTC
1 product affected across 1 vendorFleet

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.80.1
Affected range stops below 4.80.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

x_refsource_CONFIRMVendor Advisory
Source: cverecord
https://github.com/fleetdm/fleet/security/advisories/GHSA-j8h8-75h3-jg53
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/fleetdm/fleet/releases/tag/fleet-v4.80.1

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-290

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