CVE-2026-49422

HighCVSS 8.4/10Last modified Sep 1, 2026

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.

The bug may be exploitable by an unprivileged local user to escalate privileges.

Metrics

CVSS 3.1 8.4/10CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness enumeration

Affected software

No affected versions have been published.

Timeline

Published
Aug 19, 2026
Last modified
Sep 1, 2026
NVD status
Analyzed

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CVE-2026-49422: High severity, CVSS 8.4 | Vulnix