Memory Leak and Reassembly Issue in Linux Kernel's MCTP Implementation
Summary
CVE-2025-21972: In the Linux kernel, the following vulnerability has been resolved: net: mctp: unshare packets when reassembling Ensure that the frag_list used for reassembly isn't shared with other packets. 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 a core component of many operating systems, providing essential services for hardware and software interactions. It is known for its robustness, scalability, and support for a wide range of hardware architectures. The kernel's networking stack includes various protocols, including the Management Component Transport Protocol (MCTP), which is used for communication between devices. This vulnerability specifically affects the MCTP implementation, where improper handling of packet reassembly can lead to memory leaks and incorrect data processing.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the MCTP networking stack related to packet reassembly. The issue arises when the frag_list used for reassembly is shared among different packets, leading to incorrect reassembly when packets are cloned. This can result in a memory leak due to circular references between fragments and their skb_shared_info. The vulnerability is particularly relevant for the upcoming MCTP-over-USB driver, which utilizes skb_clone, potentially triggering the problem. A kunit test has been added to reproduce the issue, highlighting its significance in the kernel's networking functionality.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
Currently, no specific workaround has been provided for this vulnerability. Users are advised to apply the patch as soon as it becomes available.
Conclusion
The CVE-2025-21972 vulnerability in the Linux kernel's MCTP implementation poses significant risks related to memory management and data integrity. Users are encouraged to update their systems to the patched version as soon as it becomes available to ensure the security and stability of their applications.
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FAQ
CVE-2025-21972 is a vulnerability in the Linux kernel's MCTP implementation that can lead to memory leaks and incorrect packet reassembly.
If exploited, this vulnerability can cause memory leaks and incorrect data processing, potentially leading to system instability.
Yes, a patch is available for Debian 13 in version 6.12.20-1. Users of Debian 12 should monitor for updates.
While no specific workaround is available, it is crucial to apply the patch as soon as it is released to mitigate risks.
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