Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-07-27T00:00:00 kernel: nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CWE-911

In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path In nvmet_tcp_try_recv_ddgst(), when a data digest mismatch is detected, nvmet_req_uninit() is called unconditionally. However, if the command arrived via the nvmet_tcp_handle_req_failure() path, nvmet_req_init() had returned false and percpu_ref_tryget_live() was never executed. The unconditional percpu_ref_put() inside nvmet_req_uninit() then causes a refcount underflow, leading to a WARNING in percpu_ref_switch_to_atomic_rcu, a use-after-free diagnostic, and eventually a permanent workqueue deadlock. Check cmd->flags & NVMET_TCP_F_INIT_FAILED before calling nvmet_req_uninit(), matching the existing pattern in nvmet_tcp_execute_request().

A flaw was found in the Linux kernel's NVMe over TCP (nvmet-tcp) implementation. When a data digest mismatch occurs, a reference count underflow can happen due to an unconditional cleanup call. This issue can lead to a use-after-free condition and ultimately result in a permanent workqueue deadlock, causing a Denial of Service (DoS) for the system.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Affected kernel Red Hat Enterprise Linux 8 Affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-64534 https://nvd.nist.gov/vuln/detail/CVE-2026-64534 https://lore.kernel.org/linux-cve-announce/2026072734-CVE-2026-64534-434b@gregkh/T