Summary
nebula-mesh: Session and OIDC state cookies lack the Secure attribute
internal/web/session.go and internal/web/oidc.go set HttpOnly and SameSite=Lax on every cookie but never Secure. A single plaintext request to the origin (operator on a LAN, mistyped URL, HTTP→HTTPS not strictly enforced, reverse proxy misconfiguration) discloses the session.
Affected
All released versions up to v0.3.1.
Cookie sites
internal/web/session.go,Login,StartAuthenticatedSession,CompleteTwoFactor,Logoutinternal/web/oidc.go,HandleLogin(state set),HandleCallback(state clear)
Reproducer
Start nebula-mgmt without tls_cert/tls_key (the documented "behind a reverse proxy" deployment). Hit any login flow over the local listener:
curl -i -X POST -d 'username=admin&password=…' http://127.0.0.1:8080/ui/login
The Set-Cookie: nebula_session=… line will lack Secure. A subsequent unencrypted hop reveals the cookie verbatim.
Operational migration
Operators flipping cookie_secure on a running deployment should expect a one-time logout: existing browser cookies have the old attribute set and the new delete-cookie won't match.
Impact
An attacker who can observe one HTTP request to the origin recovers the session cookie and impersonates the operator for the remainder of its 24h TTL. The OIDC state cookie has a narrower 10-minute window but enables CSRF on the OIDC callback during that window.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Driven by an explicit cookie_secure config option, inferred true when tls_cert+tls_key are configured and false otherwise. rate_limit.trust_proxy_header is deliberately not used as a signal, that flag controls XFF parsing for rate-limit IPs and does not promise the proxy speaks TLS to clients. Operator behind a TLS-terminating proxy sets cookie_secure: true explicitly.
Logout and OIDC state-clear cookies also pick up matching HttpOnly + SameSite=Lax so browsers reliably replace the original.
Frequently Asked Questions
- What is CVE-2026-48058? CVE-2026-48058 is a medium-severity security vulnerability in github.com/juev/nebula-mesh (go), affecting versions < 0.3.2. It is fixed in 0.3.2.
- Which versions of github.com/juev/nebula-mesh are affected by CVE-2026-48058? github.com/juev/nebula-mesh (go) versions < 0.3.2 is affected.
- Is there a fix for CVE-2026-48058? Yes. CVE-2026-48058 is fixed in 0.3.2. Upgrade to this version or later.
- Is CVE-2026-48058 exploitable, and should I be worried? Whether CVE-2026-48058 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
- What actually determines whether CVE-2026-48058 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.
- How do I fix CVE-2026-48058? Upgrade
github.com/juev/nebula-meshto 0.3.2 or later.