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TI-2025-31021 Aliases CVE-2025-48865GHSA-q7p4-7xjv-j3wf

Fabio allows HTTP clients to manipulate custom headers it adds

Priority HIGH 80CWE-345Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-345.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00466 40th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed fabio (fabiolb): 1.6.6github.com/fabiolb/fabio (Go): 1.6.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
fabiolbfabiobefore 1.6.61.6.6Patch availableCNA
—github.com/fabiolb/fabio (Go)before 1.6.61.6.6Patch availableGHSA-q7p4-7xjv-j3wf
  • fabio Vendorfabiolb Affected before 1.6.6 Fixed in 1.6.6 Patch available CNA
  • github.com/fabiolb/fabio (Go) Vendor— Affected before 1.6.6 Fixed in 1.6.6 Patch available GHSA-q7p4-7xjv-j3wf

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:fabiolb:fabio:*:*:*:*:*:go:*:*before 1.6.6Vulnerablefabiolb
  • cpe:2.3:a:fabiolb:fabio:*:*:*:*:*:go:*:* Versions before 1.6.6 Vulnerable ·fabiolb

Remediation

  • Fix · CNA fabio (fabiolb) Fixed in 1.6.6
  • Fix · GHSA-q7p4-7xjv-j3wf github.com/fabiolb/fabio (Go) Fixed in 1.6.6 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-48865
  2. 2026-10-03 Alias added: GHSA-q7p4-7xjv-j3wf

References

Exploit 1

Patch 1

Advisory 1

Other 2

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences