Privilege Escalation Vulnerability in FreeBSD TCP Stack

CVE-2026-49422

What is CVE-2026-49422?

A flaw in the FreeBSD TCP stack arises from the RACK setsockopt(2) handler improperly managing the connection lock during the copying of option data from userspace. This mismanagement may allow a local user to exploit a timing window where the pointer to the TCP stack's per-connection control block becomes invalid after switching stacks. As a result, an unprivileged local user could potentially escalate their privileges, posing a significant security risk.

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