CVE-2024-50154

Name of the Vulnerable Software and Affected Versions: Linux kernel versions prior to 6.6.61

Description: A use-after-free vulnerability was reported in the Linux kernel's TCP timer handling. The issue occurs when the req->sk is closed before the timer expiration, which is 63 seconds by default. This can happen in a scenario where inet csk complete hashdance() calls inet csk reqsk queue drop(), but del timer sync() is missed, allowing the reqsk timer to continue running and sending multiple SYN+ACKs until it expires. The vulnerability can be exploited by attaching a BPF program to trace tcp retransmit synack, which passes the req->sk to the bpf sk storage get tracing kernel helper.

Recommendations: To resolve the issue, update the Linux kernel to version 6.6.61 or later. As a temporary workaround, consider disabling the bpf sk storage get tracing function until a patch is available. Restrict access to the vulnerable reqsk queue unlink function to minimize the risk of exploitation. Avoid using the timer pending() function in reqsk queue unlink() until the issue is resolved.