Critical Vulnerability in Linux Kernel: Arbitrary Write in atmtcp_recv_control
Summary
CVE-2025-39828: In the Linux kernel, the following vulnerability has been resolved: atm: atmtcp: Prevent arbitrary write in atmtcp_recv_control(). Affects linux versions 5.10.103-1 – 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 is known for its robustness and flexibility, supporting a wide range of hardware architectures. However, vulnerabilities can arise due to its complexity, and this specific issue affects the ATM (Asynchronous Transfer Mode) subsystem, particularly the atmtcp module, which facilitates TCP/IP communication over ATM networks.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the atmtcp module, specifically within the atmtcp_recv_control function. This flaw allows for arbitrary writes due to inadequate validation of message lengths when processing user-space messages. An attacker could exploit this vulnerability to overwrite kernel pointers, potentially leading to system crashes or unauthorized access to sensitive data. The issue arises from the struct atmtcp_control, which contains a space for an in-kernel pointer, allowing user-space messages to manipulate kernel memory improperly.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, users can disable the atmtcp module if it is not required for their applications. This can be done by running the command: 'sudo modprobe -r atmtcp'. However, this may impact applications relying on ATM communication.
Conclusion
The CVE-2025-39828 vulnerability in the Linux kernel's atmtcp module poses a significant risk due to its potential for arbitrary writes. Users are strongly advised to update their systems to the patched version to safeguard against exploitation. For those unable to update immediately, disabling the atmtcp module can serve as a temporary measure.
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FAQ
CVE-2025-39828 is a critical vulnerability in the Linux kernel's atmtcp module that allows for arbitrary writes due to insufficient validation of user-space messages.
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Exploitation of this vulnerability could lead to system crashes, unauthorized access to sensitive data, or other malicious activities that compromise system integrity.
Yes, a patch is available in version 6.16.5-1 of the Linux kernel. Users should update to this version or later to mitigate the risk.
If immediate updating is not possible, consider disabling the atmtcp module as a temporary workaround to reduce exposure to this vulnerability.
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