CVE-2026-24000
Fleet has a rate limiting bypass via untrusted client IP headers
Description
### Impact 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 - 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. ### Workarounds Run Fleet behind a trusted reverse proxy or load balancer that overwrites client IP headers. ### For more information If you have any questions or comments about this advisory: Email us at [security@fleetdm.com](mailto:security@fleetdm.com) Join #fleet in [osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw) ### Credits We thank @fuzzztf for responsibly reporting this issue.
How to fix CVE-2026-24000
To remediate CVE-2026-24000, upgrade the affected package to a fixed version below.
- —upgrade to 4.80.1 or later
Is CVE-2026-24000 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 4.80.1