{"id":"CVE-2026-49422","aliases":["EUVD-2026-62244"],"status":"published","title":"Use-after-free in TCP RACK stack option handler","description":"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.\n\nThe bug may be exploitable by an unprivileged local user to escalate privileges.","severity":{"version":"3.1","score":8.4,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"adp","from":"cve"},"epss":{"day":"2026-11-09","score":0.00168,"percentile":0.06043,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-416"],"published":"2026-08-19T05:28:32Z","modified":"2026-11-09T20:10:00Z","products":[{"vendor":"freebsd","product":"freebsd"}],"references":[{"url":"https://security.freebsd.org/advisories/FreeBSD-SA-26:43.tcp.asc","tags":["vendor-advisory","Vendor Advisory"]}],"sources":{"cve":[{"id":"CVE-2026-49422","title":"Use-after-free in TCP RACK stack option handler","description":"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.\n\nThe bug may be exploitable by an unprivileged local user to escalate privileges.","status":"published","published":"2026-08-19T05:28:32.468Z","modified":"2026-08-20T03:55:47.007Z","cvss":[{"version":"3.1","score":8.4,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"adp"}],"cwes":["CWE-416"],"updated_at":"2026-11-02T13:35:10.963527Z"}],"euvd":[{"id":"EUVD-2026-62244","description":"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.\n\nThe bug may be exploitable by an unprivileged local user to escalate privileges.","status":"published","published":"2026-08-19T05:28:32Z","modified":"2026-08-20T03:55:47Z","cvss":[{"version":"3.1","score":8.4,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T18:01:40.451894Z"}],"nvd":[{"id":"CVE-2026-49422","description":"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.\n\nThe bug may be exploitable by an unprivileged local user to escalate privileges.","status":"published","published":"2026-08-19T06:17:41.447Z","modified":"2026-11-09T20:10:00.2Z","cvss":[{"version":"3.1","score":8.4,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-416"],"updated_at":"2026-11-09T22:15:51.558963Z"}]}}