Vulnerability Description
Fabio is an HTTP(S) and TCP router for deploying applications managed by consul. Prior to version 1.6.6, Fabio allows clients to remove X-Forwarded headers (except X-Forwarded-For) due to a vulnerability in how it processes hop-by-hop headers. Fabio adds HTTP headers like X-Forwarded-Host and X-Forwarded-Port when routing requests to backend applications. Since the receiving application should trust these headers, allowing HTTP clients to remove or modify them creates potential security vulnerabilities. Some of these custom headers can be removed and, in certain cases, manipulated. The attack relies on the behavior that headers can be defined as hop-by-hop via the HTTP Connection header. This issue has been patched in version 1.6.6.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Fabiolb | Fabio | < 1.6.6 |
Related Weaknesses (CWE)
References
- https://github.com/fabiolb/fabio/commit/fdaf1e966162e9dd3b347ffdd0647b39dc71a1a3Patch
- https://github.com/fabiolb/fabio/releases/tag/v1.6.6Release Notes
- https://github.com/fabiolb/fabio/security/advisories/GHSA-q7p4-7xjv-j3wfExploitVendor Advisory
- https://github.com/fabiolb/fabio/security/advisories/GHSA-q7p4-7xjv-j3wfExploitVendor Advisory
FAQ
What is CVE-2025-48865?
CVE-2025-48865 is a vulnerability with a CVSS score of 9.1 (CRITICAL). Fabio is an HTTP(S) and TCP router for deploying applications managed by consul. Prior to version 1.6.6, Fabio allows clients to remove X-Forwarded headers (except X-Forwarded-For) due to a vulnerabil...
How severe is CVE-2025-48865?
CVE-2025-48865 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2025-48865?
Check the references section above for vendor advisories and patch information. Affected products include: Fabiolb Fabio.