CVE-2025-48865

Published May 30, 2025

Last updated 9 months ago

CVSS critical 9.1

Overview

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.
Source: security-advisories@github.com
NVD status: Analyzed
Products: fabio

Risk scores

CVSS 3.1

Type: Primary
Base score: 9.1
Impact score: 5.2
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Severity: CRITICAL

Weaknesses

security-advisories@github.com: CWE-345
nvd@nist.gov: CWE-345

Hype score: Not currently trending

Configurations

[
  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:fabiolb:fabio:*:*:*:*:*:go:*:*",
            "matchCriteriaId": "6A945EFC-B582-43E7-A382-9EE8DFF03511",
            "versionEndExcluding": "1.6.6",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ]
  }
]

References

Sources include official advisories and independent security research.

Overview

Risk scores

CVSS 3.1

Weaknesses

Social media

Configurations

References