Vulnerability Details CVE-2026-49422
The RACK setsockopt(2) handler drops the connection lock in order to copy option data from userspace, then reacquires the lock. After reacquiring, it verifies that the TCP stack had not been switched away, but did not reload its pointer to the stack's per-connection control block. If userspace switches stacks twice during this window, the check will succeed but the saved pointer will refer to freed memory.
The bug may be exploitable by an unprivileged local user to escalate privileges.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 2.5%
CVSS Severity
CVSS v3 Score 8.4