Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free of share_conf in compound request… (CVE-2026-23428)
A use-after-free vulnerability in the Linux kernel's ksmbd SMB network file system component was resolved. The vulnerability occurs when compound SMB2 requests reuse a tree connection object without validating its state, potentially leading to dereferencing freed memory. This flaw could allow an attacker to cause system crashes or execute arbitrary code. The issue has been fixed in updated Linux kernel versions. Users should apply the official kernel updates and reboot to mitigate the vulnerability.
AI Analysis
Technical Summary
CVE-2026-23428 is a use-after-free vulnerability in the Linux kernel's ksmbd SMB server implementation. The function smb2_get_ksmbd_tcon() reuses the work->tcon object in compound SMB2 requests without validating the tcon->t_state. While the initial lookup path checks that t_state equals TREE_CONNECTED, the compound reuse path bypasses this check. If a prior command in the compound request sets t_state to TREE_DISCONNECTED and frees share_conf, subsequent commands may dereference the freed share_conf via work->tcon->share_conf, leading to a use-after-free condition. This was detected by KASAN and affects multiple Linux kernel versions prior to the patched releases. The vulnerability has a CVSS 3.1 score of 9.8 (critical impact on confidentiality, integrity, and availability).
Potential Impact
An attacker could exploit this use-after-free vulnerability to cause system crashes or potentially execute arbitrary code with kernel privileges, compromising system confidentiality, integrity, and availability. The vulnerability affects the SMB network file system server daemon (ksmbd) in the Linux kernel. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
A patch is available and has been released by Ubuntu as part of their Linux kernel updates. Users should update their Linux kernel packages to the fixed versions listed in the Ubuntu security advisories USN-8490-1 and USN-8491-1 and reboot their systems to apply the fixes. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be necessary. Follow the vendor's update instructions carefully to fully remediate the vulnerability.
Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free of share_conf in compound request… (CVE-2026-23428)
Description
A use-after-free vulnerability in the Linux kernel's ksmbd SMB network file system component was resolved. The vulnerability occurs when compound SMB2 requests reuse a tree connection object without validating its state, potentially leading to dereferencing freed memory. This flaw could allow an attacker to cause system crashes or execute arbitrary code. The issue has been fixed in updated Linux kernel versions. Users should apply the official kernel updates and reboot to mitigate the vulnerability.
CVSS v3.1
Score 9.8critical
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 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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]?arch=source&distro=realtime/jammypkg:deb/ubuntu/[email protected]?arch=source&distro=realtime/jammypkg:deb/ubuntu/[email protected]~22.04.1?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 protected]~24.04.1?arch=source&distro=noblepkg:deb/ubuntu/[email protected]?arch=source&distro=noblepkg:deb/ubuntu/[email 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protected]~24.04.1?arch=source&distro=noblepkg:deb/ubuntu/[email protected]?arch=source&distro=noblepkg:deb/ubuntu/[email protected]?arch=source&distro=bluefield/noblepkg:deb/ubuntu/[email protected]+fips1?arch=source&distro=fips-updates/noblepkg:deb/ubuntu/[email protected]+fips1?arch=source&distro=fips-updates/noblepkg:deb/ubuntu/[email protected]+fips1?arch=source&distro=fips-updates/noblepkg:deb/ubuntu/[email protected]+fips1?arch=source&distro=fips-updates/noblepkg:deb/ubuntu/[email protected]?arch=source&distro=realtime/noblepkg:deb/ubuntu/[email protected]?arch=source&distro=realtime/noblepkg:deb/ubuntu/[email protected]~24.04.1?arch=source&distro=realtime/noblepkg:deb/ubuntu/[email 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=questingRun 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
CVE-2026-23428 is a use-after-free vulnerability in the Linux kernel's ksmbd SMB server implementation. The function smb2_get_ksmbd_tcon() reuses the work->tcon object in compound SMB2 requests without validating the tcon->t_state. While the initial lookup path checks that t_state equals TREE_CONNECTED, the compound reuse path bypasses this check. If a prior command in the compound request sets t_state to TREE_DISCONNECTED and frees share_conf, subsequent commands may dereference the freed share_conf via work->tcon->share_conf, leading to a use-after-free condition. This was detected by KASAN and affects multiple Linux kernel versions prior to the patched releases. The vulnerability has a CVSS 3.1 score of 9.8 (critical impact on confidentiality, integrity, and availability).
Potential Impact
An attacker could exploit this use-after-free vulnerability to cause system crashes or potentially execute arbitrary code with kernel privileges, compromising system confidentiality, integrity, and availability. The vulnerability affects the SMB network file system server daemon (ksmbd) in the Linux kernel. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
A patch is available and has been released by Ubuntu as part of their Linux kernel updates. Users should update their Linux kernel packages to the fixed versions listed in the Ubuntu security advisories USN-8490-1 and USN-8491-1 and reboot their systems to apply the fixes. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be necessary. Follow the vendor's update instructions carefully to fully remediate the vulnerability.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-23428
- 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"]
- Cvss Version
- 4.0
Threat ID: 6a58b4dc68715ace43dae7b3
Added to database: 07/16/2026, 10:39:24 UTC
Last enriched: 08/01/2026, 06:13:15 UTC
Last updated: 09/10/2026, 19:36:52 UTC
Views: 27
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