Linux Kernel up to 6.12.22/6.13.10/6.14.1 ksmbd smb_check_perm_dacl dacloffset null pointer dereference

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 6.12.22/6.13.10/6.14.1. This affects the function smb_check_perm_dacl of the component ksmbd. Executing a manipulation of the argument dacloffset can lead to null pointer dereference. This vulnerability appears as CVE-2025-22039. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.22/6.13.10/6.14.1. It has been declared as critical. This vulnerability affects the function smb_check_perm_dacl of the component ksmbd. The manipulation of the argument dacloffset with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix overflow in dacloffset bounds check The dacloffset field was originally typed as int and used in an unchecked addition, which could overflow and bypass the existing bounds check in both smb_check_perm_dacl() and smb_inherit_dacl(). This could result in out-of-bounds memory access and a kernel crash when dereferencing the DACL pointer. This patch converts dacloffset to unsigned int and uses check_add_overflow() to validate access to the DACL.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2025-22039 since 12/29/2024. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 240657 (Ubuntu 25.04 : Linux kernel vulnerabilities (USN-7594-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.23, 6.13.11, 6.14.2 or 6.15-rc1 eliminates this vulnerability. Applying the patch 6a9cd9ff0fa2bcc30b2bfb8bdb161eb20e44b9dc/6b8d379048b168a0dff5ab1acb975b933f368514/443b373a4df5a2cb9f7b8c4658b2afedeb16397f/beff0bc9d69bc8e733f9bca28e2d3df5b3e10e42 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (240657) and CERT Bund (WID-SEC-2025-0844). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel
• Dell Avamar
• SolarWinds Security Event Manager
• Dell NetWorker
• Dell Secure Connect Gateway
• IBM QRadar SIEM

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.13.0
• 6.13.1
• 6.13.2
• 6.13.3
• 6.13.4
• 6.13.5
• 6.13.6
• 6.13.7
• 6.13.8
• 6.13.9
• 6.13.10
• 6.14.0
• 6.14.1

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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