Critical UAF Vulnerability in Linux Kernel's SMB Client: CVE-2025-37750
Summary
CVE-2025-37750: In the Linux kernel, the following vulnerability has been resolved: smb: client: fix UAF in decryption with multichannel After commit f7025d861694 ("smb: client: allocate crypto only for primary server") and commit b0abc... Affects linux versions 6.1.106-1 – 6.9.9-1. No fix is published. How to fix ↓
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Background
The Linux kernel is the core component of many operating systems, providing essential services for hardware and software interaction. It supports various functionalities, including file systems, process management, and network protocols. The SMB (Server Message Block) client within the Linux kernel facilitates file sharing and network communication with Windows servers. This vulnerability specifically affects the SMB client, which is crucial for seamless interoperability between Linux and Windows environments.
Vulnerability Detail
CVE-2025-37750 is a use-after-free (UAF) vulnerability in the Linux kernel's SMB client, introduced after specific commits that altered how cryptographic functions were handled. The vulnerability arises when multiple threads attempt to access the same cryptographic transformation function (TFM) simultaneously, leading to potential memory corruption. This can result in a KASAN (Kernel Address Sanitizer) error, causing system instability or crashes when running specific tests against Windows Server 2022. The vulnerability poses significant risks, particularly in environments where Linux systems interact with Windows servers, potentially leading to unauthorized access or data breaches.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
Currently, no specific workarounds have been provided for this vulnerability. However, users are advised to limit the use of the SMB client in critical environments until the patch is applied.
Conclusion
CVE-2025-37750 is a critical vulnerability in the Linux kernel's SMB client that poses significant risks to systems interacting with Windows servers. Users are strongly advised to update their systems to the patched version of the Linux kernel to ensure protection against potential exploitation. Monitoring tools like Vulert can assist in identifying vulnerabilities in your software.
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FAQ
CVE-2025-37750 is a use-after-free vulnerability in the Linux kernel's SMB client that can lead to memory corruption and system instability.
This vulnerability can cause crashes or unauthorized access when the SMB client interacts with Windows servers, particularly in multi-threaded environments.
The vulnerability affects the Linux kernel versions used in Debian 12 and Debian 13, specifically in the SMB client functionality.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected by this vulnerability.
Yes, a patch has been released. Users should update their Linux kernel to the latest version to mitigate the risks associated with CVE-2025-37750.
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