CVE-2026-53274: Linux kernel · net/smc: fix sleep-inside-lock in __smc_setsockopt() causing local DoS
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-1066.69~22.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1066.69~22.04.1, 6.8.0-1070.78~22.04.1, 6.8.0-1068.75~22.04.1 +38
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and has been released in Linux kernel versions 6.8.0-1064.67~22.04.1 and later. Users should update to these fixed versions or later to remediate the vulnerability. No additional mitigation is required as the issue is resolved by the official fix.
Description
A logic flaw in the Linux kernel's net/smc subsystem in the __smc_setsockopt() function allows a local unprivileged user to cause a denial of service (DoS) by holding a socket lock indefinitely. This occurs because the function performs a user-space memory copy while holding a socket lock, which can be exploited using userfaultfd-monitored or FUSE-backed memory to halt execution and exhaust kernel worker threads, triggering the hung task watchdog. The issue has been fixed by moving the user-space copy operation outside the critical section protected by the socket lock.
References
- ubuntu.com/security/CVE-2026-53274 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-53274 (opens in a new tab)
- git.kernel.org/linus/a3fdd924d88c30b9f488636ce0e4696012cf5511 (opens in a new tab)
- git.kernel.org/stable/c/35a22117839602bb52283de08894c5a7dde92420 (opens in a new tab)
- git.kernel.org/stable/c/5d27d2ffe487df89ce28fda0410eafa05dbe03a0 (opens in a new tab)
- git.kernel.org/stable/c/89f6fbe0033c942cb790ffd53ca93a45eeaf1c91 (opens in a new tab)
- git.kernel.org/stable/c/94d286fa5eedc550d42bcb9c85416af8f77736ff (opens in a new tab)
- git.kernel.org/stable/c/a3fdd924d88c30b9f488636ce0e4696012cf5511 (opens in a new tab)
- git.kernel.org/stable/c/dcd90f42a33e4220385f27b515183d0c91b2fc4a (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-3 (opens in a new tab)