Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: af_unix: Reject SIOCATMARK on non-stream sockets SIOCATMARK reports whether the… (CVE-2026-52928)
A vulnerability in the Linux kernel's AF_UNIX socket implementation was resolved, specifically rejecting the SIOCATMARK ioctl on non-stream sockets. The SIOCATMARK ioctl is intended to report whether the receive queue is at the urgent mark for MSG_OOB, which is only supported on SOCK_STREAM sockets. Non-stream sockets like SOCK_DGRAM and SOCK_SEQPACKET do not support MSG_OOB and thus should not support SIOCATMARK. The fix returns an error for non-stream sockets before checking the receive queue. This issue was addressed in Linux kernel updates for various Ubuntu HWE edge versions.
AI Analysis
Technical Summary
The Linux kernel vulnerability CVE-2026-52928 involves improper handling of the SIOCATMARK ioctl in AF_UNIX sockets. SIOCATMARK is used to determine if the receive queue is at the urgent mark for out-of-band data (MSG_OOB), which is only valid for SOCK_STREAM sockets. However, non-stream sockets such as SOCK_DGRAM and SOCK_SEQPACKET incorrectly supported SIOCATMARK, despite rejecting MSG_OOB in sendmsg() and recvmsg(). The vulnerability was fixed by modifying the kernel to reject SIOCATMARK on non-stream sockets by returning -EOPNOTSUPP before any receive queue checks. This prevents misuse of the ioctl on unsupported socket types.
Potential Impact
The vulnerability does not affect confidentiality or integrity but has an impact on availability, as indicated by the CVSS vector (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). It could cause denial of service or kernel instability when SIOCATMARK is invoked on non-stream sockets. There are no known exploits in the wild. The issue affects local users with limited privileges and requires local access to the system.
Mitigation Recommendations
A patch is available and has been released by Ubuntu as part of their Linux kernel updates for the HWE edge and OEM kernels. Users should update their systems to the fixed kernel versions listed in the advisory and reboot to apply the changes. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be necessary. No additional mitigation steps are required beyond applying the official updates.
Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: af_unix: Reject SIOCATMARK on non-stream sockets SIOCATMARK reports whether the… (CVE-2026-52928)
Description
A vulnerability in the Linux kernel's AF_UNIX socket implementation was resolved, specifically rejecting the SIOCATMARK ioctl on non-stream sockets. The SIOCATMARK ioctl is intended to report whether the receive queue is at the urgent mark for MSG_OOB, which is only supported on SOCK_STREAM sockets. Non-stream sockets like SOCK_DGRAM and SOCK_SEQPACKET do not support MSG_OOB and thus should not support SIOCATMARK. The fix returns an error for non-stream sockets before checking the receive queue. This issue was addressed in Linux kernel updates for various Ubuntu HWE edge versions.
CVSS v3.1
Score 5.5medium
Affected software
pkg:deb/ubuntu/[email protected]~16.04.1?arch=source&distro=xenialpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.2?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.2?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.2?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]+cvm1.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.3?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/[email protected]~20.04.1?arch=source&distro=focalpkg:deb/ubuntu/[email protected]?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.2?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.2.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1?arch=source&distro=jammypkg:deb/ubuntu/[email protected]~22.04.1?arch=source&distro=jammypkg:deb/ubuntu/[email 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protected]+fips1?arch=source&distro=fips-updates/jammypkg:deb/ubuntu/[email protected]+fips1?arch=source&distro=fips-updates/jammypkg:deb/ubuntu/[email protected]+fips1?arch=source&distro=fips-updates/jammypkg:deb/ubuntu/[email protected]+fips1?arch=source&distro=fips-updates/jammypkg:deb/ubuntu/[email protected]?arch=source&distro=realtime/jammypkg:deb/ubuntu/[email protected]?arch=source&distro=realtime/jammypkg:deb/ubuntu/[email protected]~22.04.2?arch=source&distro=realtime/jammypkg:deb/ubuntu/[email protected]?arch=source&distro=noblepkg:deb/ubuntu/[email protected]?arch=source&distro=noblepkg:deb/ubuntu/[email protected]~24.04.1?arch=source&distro=noblepkg:deb/ubuntu/[email protected]~24.04.1?arch=source&distro=noblepkg:deb/ubuntu/[email protected]?arch=source&distro=noblepkg:deb/ubuntu/[email protected]~24.04.1?arch=source&distro=noblepkg:deb/ubuntu/[email protected]~24.04.1?arch=source&distro=noblepkg:deb/ubuntu/[email 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protected]~24.04.1?arch=source&distro=realtime/noblepkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resolutepkg:deb/ubuntu/[email protected]?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel vulnerability CVE-2026-52928 involves improper handling of the SIOCATMARK ioctl in AF_UNIX sockets. SIOCATMARK is used to determine if the receive queue is at the urgent mark for out-of-band data (MSG_OOB), which is only valid for SOCK_STREAM sockets. However, non-stream sockets such as SOCK_DGRAM and SOCK_SEQPACKET incorrectly supported SIOCATMARK, despite rejecting MSG_OOB in sendmsg() and recvmsg(). The vulnerability was fixed by modifying the kernel to reject SIOCATMARK on non-stream sockets by returning -EOPNOTSUPP before any receive queue checks. This prevents misuse of the ioctl on unsupported socket types.
Potential Impact
The vulnerability does not affect confidentiality or integrity but has an impact on availability, as indicated by the CVSS vector (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). It could cause denial of service or kernel instability when SIOCATMARK is invoked on non-stream sockets. There are no known exploits in the wild. The issue affects local users with limited privileges and requires local access to the system.
Mitigation Recommendations
A patch is available and has been released by Ubuntu as part of their Linux kernel updates for the HWE edge and OEM kernels. Users should update their systems to the fixed kernel versions listed in the advisory and reboot to apply the changes. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be necessary. No additional mitigation steps are required beyond applying the official updates.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-52928
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:16.04:LTS","Ubuntu:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:Nvidia-BlueField:22.04:LTS","Ubuntu:Pro:FIPS-preview:22.04:LTS","Ubuntu:Pro:FIPS-updates:22.04:LTS","Ubuntu:Pro:Realtime:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:Nvidia-BlueField:24.04:LTS","Ubuntu:Pro:FIPS-updates:24.04:LTS","Ubuntu:Pro:Realtime:24.04:LTS","Ubuntu:25.10","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
Threat ID: 6a5a017591ae9bcd3f804418
Added to database: 07/17/2026, 10:18:29 UTC
Last enriched: 09/07/2026, 23:41:48 UTC
Last updated: 09/14/2026, 22:01:35 UTC
Views: 18
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