Critical Race Condition in Linux Kernel's mremap Function - CVE-2024-50066
Summary
DEBIAN-CVE-2024-50066: In the Linux kernel, the following vulnerability has been resolved: mm/mremap: fix move_normal_pmd/retract_page_tables race In mremap(), move_page_tables() looks at the type of the PMD entry and the specified address ran... Affects linux versions < 6.11.5-1. Fixed in 6.11.5-1. How to fix ↓
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Background
The Linux kernel is the core component of many operating systems, responsible for managing hardware resources and providing essential services to software applications. It supports a wide range of functionalities, including process management, memory management, and device control. The vulnerability identified as CVE-2024-50066 affects the memory management subsystem, specifically the mremap function, which is used to resize memory mappings. This vulnerability can lead to serious security implications, including potential privilege escalation.
Vulnerability Detail
In the Linux kernel, a race condition exists in the mremap function due to improper handling of page table entries. When the mremap function is invoked, it attempts to move page table entries while holding the mmap_lock in write mode but without acquiring necessary rmap locks initially. This can lead to a scenario where concurrent processes can interfere with each other's operations, resulting in the creation of invalid PMD entries. Specifically, on x86 architectures, this could allow physical page 0 to be mapped as a page table, potentially leading to user-to-kernel privilege escalation. The vulnerability is particularly concerning as it can be exploited under specific conditions involving shared memory and file mappings.
How To Fix
Minimum fixed version
6.11.5-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade linuxTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
Currently, there are no specific workarounds mentioned for this vulnerability. However, users are advised to avoid using shared memory mappings that could trigger this race condition until the kernel is updated.
Conclusion
The CVE-2024-50066 vulnerability in the Linux kernel poses significant security risks due to a race condition in the mremap function. Users are strongly encouraged to update their systems to the patched version to mitigate potential exploitation. Monitoring tools like Vulert can assist in identifying vulnerabilities in your software.
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FAQ
CVE-2024-50066 is a vulnerability in the Linux kernel that allows for a race condition in the mremap function, potentially leading to privilege escalation.
You can use tools like Vulert to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected without any signup.
The primary risk is user-to-kernel privilege escalation, which could allow unauthorized users to gain elevated access to system resources.
Yes, a patch is available in version 6.11.5-1 of the Linux kernel. Users should update to this version or later.
While there are no specific workarounds, it is advisable to limit the use of shared memory mappings until the kernel can be updated.
References
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