What is CVE-2026-64534?

CVE-2026-64534 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, affecting Linux kernel versions from 5.10.20 onward and patched in 5.10.261, 5.15.212, 6.1.178 and others. CVE-2026-64534 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-64534?

CVE-2026-64534 has a CVSS score of 9.8 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-64534?

Yes, CVE-2026-64534 has been patched. Fixed versions include 5.10.261, 5.15.212, 6.1.178 and others. If you are running Linux kernel 5.10.20 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-64534 actively exploited?

CVE-2026-64534 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-64534

Critical

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().

Package Linux Kernel

Published 2026-07-27

Last modified 2026-08-05

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.8

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Affected versions

Linux kernel versions 5.10.20, 5.11.3, 5.12 and later are affected. Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1 and their respective stable series.

Affected from

≥ 5.10.20 ≥ 5.11.3 ≥ 5.12

Fixed in

✓ 5.10.261 5.10.x ✓ 5.15.212 5.15.x ✓ 6.1.178 6.1.x ✓ 6.6.145 6.6.x ✓ 6.12.97 6.12.x ✓ 6.18.40 6.18.x ✓ 7.1

References

7 total

Showing 5 of 7 references View all on NVD

Details

CVE ID CVE-2026-64534

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-07-27

Modified 2026-08-05

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-64534?

CVE-2026-64534 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 5.10.20 onward and has been patched in 5.10.261, 5.15.212, 6.1.178 and others. CVE-2026-64534 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-64534?

CVE-2026-64534 has a CVSS score of 9.8 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-64534?

Yes. CVE-2026-64534 has been patched. Fixed versions include 5.10.261, 5.15.212, 6.1.178 and others. If you are running Linux kernel 5.10.20 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-64534 actively exploited?

No. CVE-2026-64534 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.