CVE-2023-52523

This Linux kernel vulnerability in the sockmap subsystem occurs when a BPF sk_msg program attempts to redirect a message's egress from a TCP socket to a non-TCP socket, such as UDP. Because the underlying kernel call-chain hardcoded the assumption that the target would always be a TCP socket, this invalid downcast leads to a NULL pointer dereference and a subsequent kernel crash. The issue is resolved in patched kernel versions by explicitly rejecting non-TCP redirect targets for sk_msg programs, safely returning an EACCES error rather than crashing the system.

This vulnerability is rated as Low severity because exploiting it requires privileged access, specifically capabilities such as CAP_BPF or CAP_NET_ADMIN, to load and configure custom eBPF programs on the host. An attacker with sufficient privileges could trigger a system crash by redirecting traffic to an incompatible socket type via sockmap programs, resulting in a local denial of service. The flaw cannot be leveraged remotely and does not facilitate privilege escalation or data exposure.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.