CVE-2026-64534: nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-27 · updated 2026-10-19
Weakness: CWE-667

Description

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().

Affected products

Linux kernel: from 5.10.20 before 5.10.261; from 5.11.3 before 5.12; 5.12 — fixed in 5.10.261, 5.12, 7.1

How to fix

Upgrade to a fixed version: Linux kernel 5.10.261, 5.12, 7.1. Check the vendor advisory for mitigations.

References

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