Copyright © 2012 Red Hat, Inc. All rights reserved. Low 2026-06-25T00:00:00 kernel: net/smc: fix sleep-inside-lock in __smc_setsockopt() causing local DoS 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-821

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.

A flaw was found in the Linux kernel's net/smc component. A local unprivileged user can exploit a logic flaw, specifically a 'sleep-inside-lock' issue within the __smc_setsockopt() function. By providing a specially crafted memory page, an attacker can cause the system to halt execution, leading to a Denial of Service (DoS) by exhausting kernel resources and triggering a hung task watchdog.

Red Hat Enterprise Linux 10 Fix deferred 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 Fix deferred kernel Red Hat Enterprise Linux 8 Fix deferred kernel-rt Red Hat Enterprise Linux 9 Fix deferred kernel Red Hat Enterprise Linux 9 Fix deferred kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-53274 https://nvd.nist.gov/vuln/detail/CVE-2026-53274 https://lore.kernel.org/linux-cve-announce/2026062519-CVE-2026-53274-dd59@gregkh/T