CVE-2026-47723

nebula-mesh: Web UI and API responses lack security headers (CSP, X-Frame-Options, HSTS, etc.)

None of the response paths in internal/web/ or internal/api/ set the standard browser-security headers. grep for Content-Security-Policy, X-Frame-Options, Strict-Transport-Security, X-Content-Type-Options, Referrer-Policy returns zero matches across the codebase.

Affected

All released versions up to v0.3.0.

The admin UI signs CA certificates, mints API keys (returned inline once per page), displays TOTP QR codes, and exposes operator-management forms. Missing X-Frame-Options: DENY / frame-ancestors 'none' is a real clickjacking lever against an admin browsing /ui/operators/* or /ui/cas/*. Missing X-Content-Type-Options: nosniff allows MIME confusion on any user-supplied content surface. Missing HSTS on TLS deployments leaves a downgrade window.

Kodem intelligence

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A single response-header middleware mounted at the chi router root in both /ui/* and /api/* paths:

func securityHeadersMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
        h := rw.Header()
        h.Set("Content-Security-Policy",
            "default-src 'self'; frame-ancestors 'none'; base-uri 'none'; form-action 'self'")
        h.Set("X-Content-Type-Options", "nosniff")
        h.Set("Referrer-Policy", "same-origin")
        h.Set("X-Frame-Options", "DENY")  // belt-and-braces; CSP frame-ancestors is the modern path
        if r.TLS != nil {
            h.Set("Strict-Transport-Security", "max-age=31536000; includeSubDomains")
        }
        next.ServeHTTP(rw, r)
    })
}

The inline <script> in layout.html for CSRF wiring (added in the CSRF advisory) will need either a nonce, a hash in CSP, or external-file extraction. Easiest path: a nonce per request (crypto/rand, base64) injected into both the CSP header and the script's nonce="" attribute.

1. What is CVE-2026-47723? CVE-2026-47723 is a high-severity security vulnerability in github.com/juev/nebula-mesh (go), affecting versions <= 0.3.0. It is fixed in 0.3.1.
2. Which versions of github.com/juev/nebula-mesh are affected by CVE-2026-47723? github.com/juev/nebula-mesh (go) versions <= 0.3.0 is affected.
3. Is there a fix for CVE-2026-47723? Yes. CVE-2026-47723 is fixed in 0.3.1. Upgrade to this version or later.
4. Is CVE-2026-47723 exploitable, and should I be worried? Whether CVE-2026-47723 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2026-47723 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2026-47723? Upgrade github.com/juev/nebula-mesh to 0.3.1 or later.

Other vulnerabilities in github.com/juev/nebula-mesh