CVE-2026-54761

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data exposure.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-06-23 20:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-26 16:37 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 6.0 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-06-23 20:16 UTC

Last modified

2026-06-26 16:37 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-284 · Improper access control

Record status

Analyzed

Affected

• Traefik < 3.6.21
• Traefik < 3.7.5

Attack profile CVSS 4.0 · 6.0

Attack vector

Network

Complexity

Low

Attack requirements

Present

Privileges needed

Low

User interaction

None

Confidentiality

High

Integrity

Low

Availability

None

Is it in your code?

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