VulnerabilityPublished 25 Jun 2026Updated 6 Nov 2026

CVE-2026-53274: Linux kernel · net/smc: fix sleep-inside-lock in __smc_setsockopt() causing local DoS

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in dcd90f42a33e4220385f27b515183d0c91b2fc4a : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:49 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in dcd90f42a33e4220385f27b515183d0c91b2fc4a, a3fdd924d88c30b9f488636ce0e4696012cf5511, 94d286fa5eedc550d42bcb9c85416af8f77736ff +3

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ a6a6fe27bab48f0d09a64b051e7bde432fcae081, < dcd90f42a33e4220385f27b515183d0c91b2fc4a	Fixed in dcd90f42a33e4220385f27b515183d0c91b2fc4a
LinuxLinux	Affected ≥ a6a6fe27bab48f0d09a64b051e7bde432fcae081, < a3fdd924d88c30b9f488636ce0e4696012cf5511	Fixed in a3fdd924d88c30b9f488636ce0e4696012cf5511
LinuxLinux	Affected ≥ a6a6fe27bab48f0d09a64b051e7bde432fcae081, < 94d286fa5eedc550d42bcb9c85416af8f77736ff	Fixed in 94d286fa5eedc550d42bcb9c85416af8f77736ff
LinuxLinux	Affected ≥ a6a6fe27bab48f0d09a64b051e7bde432fcae081, < 89f6fbe0033c942cb790ffd53ca93a45eeaf1c91	Fixed in 89f6fbe0033c942cb790ffd53ca93a45eeaf1c91
LinuxLinux	Affected ≥ a6a6fe27bab48f0d09a64b051e7bde432fcae081, < 35a22117839602bb52283de08894c5a7dde92420	Fixed in 35a22117839602bb52283de08894c5a7dde92420
LinuxLinux	Affected ≥ a6a6fe27bab48f0d09a64b051e7bde432fcae081, < 5d27d2ffe487df89ce28fda0410eafa05dbe03a0	Fixed in 5d27d2ffe487df89ce28fda0410eafa05dbe03a0

Description

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.

References

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