Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
Traefik: Kubernetes Gateway crossProviderNamespaces bypass allows HTTPRoute outside the allowlist to expose internal Traefik services
AV AC AT PR UI VC VI VA CVSS EPSS %ile KEV
N L P L N H L N 6.0 .0032 24.7 —
AFFECTED
Product Versions Fixed
traefik < 3.6.21 – —
TIMELINE
Jun 15 Reserved by GitHub_M
Jun 23 EXPLOIT PUBLISHED — CVE-2026-54761 (traefik). Public exploit reference added.
Jun 23 Published (CNA: GitHub_M)
Description
Traefik is an HTTP reverse proxy and load balancer. Prior to 3.6.21 and 3.7.5, there is a high severity vulnerability in Traefik's Kubernetes Gateway provider affecting the crossProviderNamespaces allowlist. For HTTPRoute rules that declare multiple (WRR) backendRefs, Traefik evaluates the allowlist against the target backendRef.namespace instead of the route's own namespace. As a result, an HTTPRoute created in a namespace that is not allow-listed can reference a cross-provider TraefikService such as api@internal, dashboard@internal or rest@internal by pointing backendRef.namespace at an allow-listed namespace covered by a Gateway API ReferenceGrant, exposing internal Traefik services on the data plane. Exploitation requires the ability to create an accepted HTTPRoute and a matching ReferenceGrant from an allow-listed namespace; it does not require any change to Traefik static configuration, RBAC, or the deployment itself. This vulnerability is fixed in 3.6.21 and 3.7.5.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| June 15, 2026 | Reserved | Reserved by GitHub_M |
| June 23, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-54761 (traefik). Public exploit reference added. |
| June 23, 2026 | Published | Published (CNA: GitHub_M) |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| traefik | traefik | — | < 3.6.21 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-54761 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.