Shift-Out-of-Bounds Vulnerability in Linux Kernel - CVE-2025-21724
Summary
CVE-2025-21724: In the Linux kernel, the following vulnerability has been resolved: iommufd/iova_bitmap: Fix shift-out-of-bounds in iova_bitmap_offset_to_index() Resolve a UBSAN shift-out-of-bounds issue in iova_bitmap_offset_to_index()... Affects linux versions < 6.1.129-1. Fixed in 6.1.129-1. 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 interactions. It is known for its robustness, flexibility, and extensive support for various hardware architectures. However, like any complex software, it is susceptible to vulnerabilities that can impact system stability and security. CVE-2025-21724 highlights a specific issue within the iommufd/iova_bitmap component, which can lead to undefined behavior due to improper handling of data types during bit manipulation.
Vulnerability Detail
CVE-2025-21724 is a shift-out-of-bounds vulnerability that arises in the iova_bitmap_offset_to_index() function of the Linux kernel. The issue occurs when the constant '1' (an integer) is shifted by bitmap->mapped.pgshift (an unsigned long value). If pgshift exceeds 31, the shift operation results in an overflow, leading to undefined behavior. This vulnerability can potentially allow an attacker to exploit the system, causing crashes or unpredictable behavior, thereby compromising the integrity of the kernel and the overall system.
How To Fix
Minimum fixed version
6.1.129-1
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 provided for this vulnerability. The best course of action is to apply the patch by updating the Linux kernel as mentioned above.
Conclusion
CVE-2025-21724 is a significant vulnerability in the Linux kernel that can lead to undefined behavior due to improper data type handling. Users are strongly encouraged to update their systems to the latest patched version of the Linux kernel to mitigate potential risks associated with this vulnerability.
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FAQ
CVE-2025-21724 is a vulnerability in the Linux kernel that can lead to undefined behavior due to a shift-out-of-bounds issue in the iova_bitmap_offset_to_index() function.
Exploitation of this vulnerability could lead to system crashes or unpredictable behavior, potentially compromising the integrity and security of the system.
Yes, a patch has been released, and users are advised to update their Linux kernel to the latest version to mitigate this vulnerability.
You can update your Linux kernel by running the command: 'sudo apt-get update && sudo apt-get upgrade linux' in your terminal.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in real-time. By using the Vulert playground at Vulert Scanner, you can check if your application is affected without requiring any signup.
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