# CVE-2026-54761: Traefik: Kubernetes Gateway crossProviderNamespaces bypass allows HTTPRoute outside the allowlist to expose internal Traefik services

> Attackers can expose internal Traefik services by bypassing namespace allowlists in Kubernetes Gateway HTTPRoute configurations.

- **Severity:** Medium 6.0 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Jun 2026
- **Updated:** 25 Jun 2026
- **Also known as:** GHSA-3g6v-2r68-prfc, GO-2026-5083, MINI-85w5-hj2c-f94g, MINI-cfrm-3mmp-vww9, MINI-mxxh-j2pp-8vgh

## What is CVE-2026-54761?

CVE-2026-54761 is a medium-severity missing authorization vulnerability in Traefik Traefik, published on 23 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-863 (Incorrect Authorization), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2026-54761?

11 open source packages ship an affected version, including github.com/traefik/traefik/v3, github.com/traefik/traefik and github.com/traefik/traefik/v2. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.6.21, 3.7.5 |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.6.21 |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.6.21 |
| `github.com/traefik/traefik/v3` | Go | From 3.7.0-ea.1 | 3.7.5 |
| `github.com/traefik/traefik/v3` | Go | From 3.7.0-ea.1 | 3.7.5 |
| `github.com/traefik/traefik` | Go | All versions | None |
| `github.com/traefik/traefik` | Go | All versions to 1.7.34 | None |
| `github.com/traefik/traefik` | Go | All versions to 1.7.34 | None |
| `github.com/traefik/traefik/v2` | Go | All versions | None |
| `github.com/traefik/traefik/v2` | Go | All versions to 2.11.50 | None |
| `github.com/traefik/traefik/v2` | Go | All versions to 2.11.50 | None |

Products: Traefik Traefik.

## How do I fix CVE-2026-54761?

Upgrade github.com/traefik/traefik/v3 to a fixed version for your release line: 3.6.21 or 3.7.5.

## Is CVE-2026-54761 being exploited?

There is no known exploitation of CVE-2026-54761 in the wild and no public exploit code.

Public exploit code:

- https://github.com/Saku0512/CVE-2026-54761-poc (github_poc): https://github.com/Saku0512/CVE-2026-54761-poc

## Other vulnerabilities in Traefik Traefik

- [CVE-2024-45410](https://insights.sbomify.com/CVE-2024-45410/): HTTP client can remove the X-Forwarded headers in Traefik (critical 9.8)
- [CVE-2026-88877](https://insights.sbomify.com/CVE-2026-88877/): Traefik v3.7.0 Authentication Bypass via from-to-www-redirect (critical 9.3)
- [CVE-2026-85595](https://insights.sbomify.com/CVE-2026-85595/): Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth (critical 9.3)
- [CVE-2026-88007](https://insights.sbomify.com/CVE-2026-88007/): Traefik HTTP/3 Backend NTLM Connection Reuse (critical 9.1)
- [CVE-2026-88009](https://insights.sbomify.com/CVE-2026-88009/): Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54761 and fix it if it is affected.

What it is: CVE-2026-54761 is a medium-severity missing authorization vulnerability in Traefik Traefik, published on 23 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-54761 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.21, 3.7.5
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.21
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.21
- github.com/traefik/traefik/v3 (Go): affected from 3.7.0-ea.1; fixed in 3.7.5
- github.com/traefik/traefik/v3 (Go): affected from 3.7.0-ea.1; fixed in 3.7.5
- github.com/traefik/traefik (Go): affected all versions; no fix listed
- github.com/traefik/traefik (Go): affected all versions up to 1.7.34; no fix listed
- github.com/traefik/traefik (Go): affected all versions up to 1.7.34; no fix listed
- github.com/traefik/traefik/v2 (Go): affected all versions; no fix listed
- github.com/traefik/traefik/v2 (Go): affected all versions up to 2.11.50; no fix listed
- github.com/traefik/traefik/v2 (Go): affected all versions up to 2.11.50; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-54761/ (Markdown: https://insights.sbomify.com/CVE-2026-54761/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54761
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54761
- OSV: https://osv.dev/vulnerability/CVE-2026-54761

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54761/
Summaries are generated and may contain mistakes; the official description above is the record.