GO-2026-5152

The SNICheck middleware in Traefik ignores wildcard TLSOptions mappings, allowing an unauthenticated attacker to bypass mTLS requirements by using a domain-fronted request. This occurs because the middleware compares the TLS options name used during the handshake with a pre-computed value that may not account for wildcard matches correctly when certain configuration models are applied.

Database specific

{
    "review_status": "REVIEWED",
    "url": "https://pkg.go.dev/vuln/GO-2026-5152"
}

References

Affected packages

Go / github.com/traefik/traefik/v2

Package

Name: github.com/traefik/traefik/v2; View open source insights on deps.dev
Purl: pkg:golang/github.com/traefik/traefik/v2

Affected ranges

Type: SEMVER
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

2.11.48

Ecosystem specific

{
    "imports": [
        {
            "path": "github.com/traefik/traefik/v2/pkg/middlewares/snicheck",
            "symbols": [
                "SNICheck.ServeHTTP"
            ]
        }
    ]
}

Database specific

source

"https://vuln.go.dev/ID/GO-2026-5152.json"

Go / github.com/traefik/traefik/v3

Package

Name: github.com/traefik/traefik/v3; View open source insights on deps.dev
Purl: pkg:golang/github.com/traefik/traefik/v3

Affected ranges

Type: SEMVER
Events: Introduced

3.7.0

Fixed

3.7.3

Ecosystem specific

{
    "imports": [
        {
            "path": "github.com/traefik/traefik/v3/pkg/middlewares/snicheck",
            "symbols": [
                "SNICheck.ServeHTTP"
            ]
        }
    ]
}

Database specific

source

"https://vuln.go.dev/ID/GO-2026-5152.json"