CVE-2025-48865
fabio vulnerability - fabiolb
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.
Affected Systems
| Vendor | fabiolb |
| Product | fabio |
| Affected Versions | before 1.6.6 |
| CWE ID | CWE-345 |
Mitigation
Apply the latest security patches from the vendor, restrict network exposure where applicable, and monitor for exploitation attempts.
Fix Instructions
Refer to the vendor advisory and apply the latest security updates. See references for detailed patching instructions.
References
Risk Assessment
CVSS: 9.1/10
| Exploit Available | Unknown |
| Patch Available | Yes |
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