CVE intelligence

CVE-2026-53274

Vulnerability intelligence

Published Jun 25, 2026Sources checked Nov 12, 2026

5.5MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2026-53274 and is rated Medium severity with a CVSS score of 5.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Jun 28, 2026

CBL-Mariner Releases

Vendor-listed releases

6.6.143.1-1

CISA KEVNot listedBased on the latest collected catalog

EPSS0.1%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-53274?

In the Linux kernel, the following vulnerability has been resolved:

net/smc: fix sleep-inside-lock in __smc_setsockopt() causing local DoS

A logic flaw in __smc_setsockopt() allows a local unprivileged user to cause a Denial of Service (DoS) by holding the socket lock indefinitely.

The function __smc_setsockopt() calls copy_from_sockptr() while holding lock_sock(sk). By passing a userfaultfd-monitored memory page (or FUSE-backed memory on systems where unprivileged userfaultfd is disabled) as the optval, an attacker can halt execution during the copy operation, keeping the lock held.

Combined with asynchronous tear-down operations like shutdown(), this exhausts the kernel wq (kworkers) and triggers the hung task watchdog.

[ 240.123456] INFO: task kworker/u8:2 blocked for more than 120 seconds. [ 240.123489] Call Trace: [ 240.123501] smc_shutdown+... [ 240.123512] lock_sock_nested+...

This patch moves the user-space copy outside the lock_sock() critical section to prevent the issue.

Source: NVD