Description

KubeSphere through 4.1.3 contains a server-side request forgery vulnerability in the git credential verification endpoint that accepts unvalidated caller-supplied URLs without allowlist restrictions. Authenticated attackers can supply arbitrary URLs to reach internal services and exfiltrate basic-auth credentials from Secrets in any namespace by leveraging the endpoint's error response handling.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.7",
  "pubDate": "2026-09-15T11:17:12.897Z",
  "pubdate": "2026-09-15T11:17:12.897Z",
  "executiveSummary": "A Server-Side Request Forgery (SSRF) vulnerability exists in the git credential verification endpoint of KubeSphere versions up to 4.1.3.\nThe vulnerability stems from the application's failure to implement an allowlist or validation logic for user-supplied URLs passed to the git verification mechanism.\nAuthenticated attackers can abuse this flaw to force the KubeSphere server to perform requests against arbitrary internal network resources.\nBy manipulating the endpoint to interact with internal services and analyzing the application's detailed error response handling, attackers can exfiltrate sensitive basic-auth credentials stored in Kubernetes Secrets across any namespace.\nThis vulnerability poses a significant risk to the integrity and confidentiality of the Kubernetes cluster, as it allows an authenticated user with access to the KubeSphere dashboard to escalate privileges or compromise internal system components.\nExploitation requires valid user authentication within the KubeSphere environment to access the vulnerable endpoint.",
  "technicalDetails": "The vulnerability resides in the git credential verification component of KubeSphere, which handles external requests for repository validation. The root cause is the lack of server-side URL validation or an allowlist mechanism when processing user-provided input in this endpoint.\nWhen a request is submitted to the git credential verification endpoint, the application processes the URL parameter provided by the caller without verifying the destination's legitimacy. An attacker can supply internal loopback addresses (127.0.0.1) or internal cluster service addresses (e.g., in-cluster Kubernetes API or metadata services) to force the backend to perform server-side requests to unauthorized locations.\nThe exploitation flow initiates when an authenticated user sends a malicious payload to the affected endpoint. The backend attempts to connect to the attacker-specified URL. Because the application processes these requests with the privileges of the KubeSphere service account, it gains access to internal network zones that are not typically exposed to the client-side user.\nA critical component of this exploit is the error response handling mechanism. When the backend attempts to verify the git credentials against the attacker-supplied URL, it returns descriptive error messages based on the connection outcome or the service's response. Attackers can leverage these error messages to infer the presence and configuration of internal services, as well as extract sensitive data.\nSpecifically, the vulnerability allows the attacker to reach internal Kubernetes Secrets by inducing the backend to interact with specific services. By observing the structured error outputs, an attacker can exfiltrate basic-auth credentials stored in these Secrets. This enables the exfiltration of credentials from any namespace within the cluster, as the KubeSphere backend often operates with broad cross-namespace permissions.\nThe vulnerability impacts KubeSphere versions through 4.1.3. Because the exploitation relies on the server-side processing of untrusted input, the KubeSphere control plane effectively acts as a proxy for the attacker, bypassing perimeter security and internal network segmentations. Successful exploitation results in full disclosure of cluster secrets available to the KubeSphere service principal, facilitating further unauthorized access or lateral movement within the container orchestration environment."
}