CVE-2026-24000 Fleet has a rate limiting bypass via untrusted client IP headers
Attackers can bypass IP-based rate limits in Fleet by spoofing client IP headers, facilitating brute-force attacks against authentication endpoints.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-24000?
CVE-2026-24000 is a medium-severity vulnerability in fleetdm fleet, published on 14 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-290
Which versions are affected by CVE-2026-24000?
3 open source packages ship an affected version, including github.com/fleetdm/fleet/v4. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/fleetdm/fleet/v4 Go | All versions | 4.80.1 |
github.com/fleetdm/fleet/v4 Go | All versions | 4.80.1 |
github.com/fleetdm/fleet/v4 Go | All versions | 4.80.1 |
Products include Fleetdm Fleet.
How do I fix CVE-2026-24000?
Upgrade github.com/fleetdm/fleet/v4 to 4.80.1 or later.
Is CVE-2026-24000 being exploited?
There is no known exploitation of CVE-2026-24000 in the wild and no public exploit code.
Other vulnerabilities in fleetdm fleet
- CVE-2020-26276 SAML authentication vulnerability in Fleet
- CVE-2026-103264 Fleet before 4.87.0 Authentication Bypass via Device Identifiers
- CVE-2026-23518 Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment
- CVE-2026-26062 Fleet server may terminate unexpectedly when handling certain gRPC requests
- CVE-2026-26061 Fleet's unbounded request body read allows remote Denial of Service
Sources
Also known as GHSA-j8h8-75h3-jg53, GO-2026-5455.