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Fencer Vulns
medium 5.8

CVE-2026-54764 json

ForwardAuth middleware leaks X-Forwarded-Port spoofing via untrusted X-Forwarded-Proto when trustForwardHeader=false

published 2026-07-06 4 mo ago modified 2026-08-18 2 mo ago also GHSA-3q9r-p662-5j8m , GO-2026-6202 , EUVD-2026-41937

cvss
5.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's ForwardAuth middleware, even when configured with trustForwardHeader: false, derives the X-Forwarded-Port header sent to the authentication service from the original incoming request instead of the sanitized forwarded request. As a result, an unauthenticated remote attacker can inject an X-Forwarded-Proto: https header over a plain HTTP connection and cause Traefik to forward X-Forwarded-Port: 443 to the authentication service, bypassing port-based authorization checks. This issue is fixed in versions v2.11.51, v3.6.22, and v3.7.6.

Patch / fix

  • go github.com/traefik/traefik/v2 2.11.51
  • go github.com/traefik/traefik/v3 3.6.22, 3.7.6
  • traefik traefik 2.11.51, 3.6.22, 3.7.6
  • govulncheck-vulndb SLES for SAP applications 16.0, SLES 16.0 0.0.20260827T195228-160000.1.1

suse advisories SUSE-SU-2026:23625-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260827T195228-160000.1.1
  • traefik openSUSE Tumbleweed 3.7.7-1.1
  • traefik2 openSUSE Tumbleweed 2.11.52-1.1

opensuse advisories openSUSE-SU-2026:21761-1openSUSE-SU-2026:11251-1openSUSE-SU-2026:11243-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-54764 updated cvss 5.8

traefik: Traefik: Authorization bypass in ForwardAuth middleware via forged X-Forwarded-Port

  • Red Hat OpenShift Dev Spaces devspaces/traefik-rhel9
    affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
GitHub 3.1 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
go github.com/traefik/traefik/v2
<2.11.51
2.11.51
go github.com/traefik/traefik/v3
<3.6.22
>=3.7.0, <3.7.6
3.6.22
3.7.6
go github.com/traefik/traefik
<=1.7.34
all versions
 no fix listed

Affected products

  • traefik traefik

Classification

Weakness
  • CWE-345 Insufficient Verification of Data Authenticity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.