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Fencer Vulns
high 8.5

CVE-2026-54765 json

Traefik: Gateway HTTPRoute backendRef filters can leak backend context across routes sharing a Service:port

published 2026-07-06 4 mo ago modified 2026-08-18 2 mo ago also GHSA-6p8f-p8j2-rqmv , GO-2026-6205 , EUVD-2026-41938

cvss
8.5
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 28%
public exploits
0
none known

Summary

Traefik is an open source HTTP reverse proxy and load balancer. From v3.7.0 prior to v3.7.6, Traefik's Kubernetes Gateway API provider may resolve two accepted HTTPRoutes that target the same backend Service:port but configure different backendRef filters to the same child service and apply only one route's filter set to all requests reaching that backend. In Gateway deployments where backendRef filters set security-sensitive headers, such as tenant identity, authorization context, or values the backend trusts, an attacker who can create an accepted HTTPRoute sharing the same backend Service:port may cause their route's filter context to be applied to another route's requests, potentially crossing namespace boundaries when a ReferenceGrant permits cross-namespace targeting. This issue is fixed in version v3.7.6.

Patch / fix

  • go github.com/traefik/traefik/v3 3.7.6
  • traefik traefik 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

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

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-2026-54765 updated cvss 8.5

traefik: Traefik: Unauthorized filter context application in Kubernetes Gateway API provider

  • 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
total
Assessed
4 mo ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:H/SA:N
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:H/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 8.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N

Affected packages

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

Affected products

  • traefik traefik

Classification

Weakness

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.