Linkerd is an open source, ultralight, security-first service mesh for Kubernetes. In affected versions when the application being run by linkerd is susceptible to SSRF, an attacker could potentially trigger a denial-of-service (DoS) attack by making requests to localhost:4191/shutdown. Linkerd could introduce an optional environment variable to control a token that must be passed as a header. Linkerd should reject shutdown requests that do not include this header. This issue has been addressed in release version edge-24.6.2 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.