Answer in brief
CVE-2026-24000 records a Medium severity (CVSS 5.3) vulnerability in Fleet has a rate limiting bypass via untrusted client IP headers. The current sources do not mark it as known exploited. The current feed maps github.com/fleetdm/fleet/v4 (go). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps github.com/fleetdm/fleet/v4 (go). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| github.com/fleetdm/fleet/v4go | <4.80.1 | 4.80.1 |
Published upstream
May 14, 2026
Evidence: source:ghsa:source_dates:source-dates:recordSource modified
Sep 6, 2026
Evidence: source:ghsa:source_dates:source-dates:recordFirst seen by HOL
Sep 6, 2026
### 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]](mailto:[email protected]) 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.
Quoted source text, attributed separately from HOL analysis.