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TI-2026-44991 Aliases CVE-2026-62987GHSA-fq95-v8xc-jm3v

Authentication bypass by spoofing in fabiolb fabio

Priority HIGH 65CWE-290Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-290.

Summary

Fabio is an HTTP(S) and TCP router for deploying applications managed by consul. From 1.6.6 until 1.7.2, the CVE-2025-48865 fix in proxy/http_headers.go uses protectHeaders for a hardcoded set of forwarded headers but omits the operator-configured ClientIPHeader, TLSHeader, and RequestID names. In proxy/http_proxy.go, HTTPProxy.ServeHTTP calls addHeaders to set these trust headers before Go ReverseProxy processes the inbound Connection header, allowing an unauthenticated client to name and remove the configured headers before the request reaches the backend. Deployments that enable the corresponding proxy.header options can therefore lose client-IP, TLS-termination, or request-correlation signals used by backend authorization and auditing; the options are empty by default, and the hardcoded protected forwarded headers are unaffected. This issue is fixed in version 1.7.2.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00202 10th percentileScored 2026-11-07
Fix Fixed fabio (fabiolb): 1.7.2github.com/fabiolb/fabio (Go): 1.7.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

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

Affected products

VendorProductAffected versionsFixed inStatusSource
fabiolbfabio1.6.6 to before 1.7.21.7.2Patch availableCNA
—github.com/fabiolb/fabio (Go)1.6.6 to before 1.7.21.7.2Patch availableGHSA-fq95-v8xc-jm3v
  • fabio Vendorfabiolb Affected 1.6.6 to before 1.7.2 Fixed in 1.7.2 Patch available CNA
  • github.com/fabiolb/fabio (Go) Vendor— Affected 1.6.6 to before 1.7.2 Fixed in 1.7.2 Patch available GHSA-fq95-v8xc-jm3v

Remediation

  • Fix · CNA fabio (fabiolb) Fixed in 1.7.2
  • Fix · GHSA-fq95-v8xc-jm3v github.com/fabiolb/fabio (Go) Fixed in 1.7.2 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-62987
  2. 2026-10-03 Alias added: GHSA-fq95-v8xc-jm3v

References

Advisory 1

Other 4

  • TI-2025-31021 Fabio allows HTTP clients to manipulate custom headers it adds CVSS 3.1CRITICAL 9.1

Sources

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