GHSA-j8h8-75h3-jg53 Fleet has a rate limiting bypass via untrusted client IP headers

• Go github.com/fleetdm/fleet/v4: < 4.80.1 → fixed in 4.80.1

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 [email protected] Join #fleet in osquery Slack Credits We thank @fuzzztf for responsibly reporting this issue.