CVE-2026-64534

CRITICAL CVSS 3.1: 9.8 EPSS 0.16%
Updated Jul 30, 2026
Linux
Parameter Value
CVSS 9.8 (CRITICAL)
Affected Versions before 7.1
Fixed In 5.10.261
Vendor Linux
Public PoC No

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().

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Vulnerable Products 7

Configuration From (including) Up to (excluding)
Linux Linux_Kernel
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
5.10.261
Linux Linux_Kernel
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
5.15.212
Linux Linux_Kernel
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
6.1.178
Linux Linux_Kernel
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
6.6.145
Linux Linux_Kernel
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
6.12.97
Linux Linux_Kernel
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
6.18.40
Linux Linux_Kernel
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
7.1