What is the severity of CVE-2025-21686?

CVE-2025-21686 is a vulnerability in the Linux kernel that entails a medium severity level due to the potential for resource accounting issues.

How do I fix CVE-2025-21686?

To fix CVE-2025-21686, update your Linux kernel to the latest patched version provided by your distribution.

What versions of the Linux kernel are affected by CVE-2025-21686?

CVE-2025-21686 affects multiple versions of the Linux kernel that support io_uring with the IORING_REGISTER_CLONE_BUFFERS feature.

What type of vulnerability is CVE-2025-21686?

CVE-2025-21686 is a resource management vulnerability related to io_uring and buffer cloning in the Linux kernel.

Is there any exploit available for CVE-2025-21686?

As of the current information, there are no publicly known exploits for CVE-2025-21686.

Vulnerability/
CVE-2025-21686

10/2/2025

CVE-2025-21686: io_uring/rsrc: require cloned buffers to share accounting contexts

First published: Mon Feb 10 2025(Updated: )

In the Linux kernel, the following vulnerability has been resolved: io_uring/rsrc: require cloned buffers to share accounting contexts When IORING_REGISTER_CLONE_BUFFERS is used to clone buffers from uring instance A to uring instance B, where A and B use different MMs for accounting, the accounting can go wrong: If uring instance A is closed before uring instance B, the pinned memory counters for uring instance B will be decremented, even though the pinned memory was originally accounted through uring instance A; so the MM of uring instance B can end up with negative locked memory.

Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Affected Software	Affected Version	How to fix
Linux Kernel

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Frequently Asked Questions

What is the severity of CVE-2025-21686?
CVE-2025-21686 is a vulnerability in the Linux kernel that entails a medium severity level due to the potential for resource accounting issues.
How do I fix CVE-2025-21686?
To fix CVE-2025-21686, update your Linux kernel to the latest patched version provided by your distribution.
What versions of the Linux kernel are affected by CVE-2025-21686?
CVE-2025-21686 affects multiple versions of the Linux kernel that support io_uring with the IORING_REGISTER_CLONE_BUFFERS feature.
What type of vulnerability is CVE-2025-21686?
CVE-2025-21686 is a resource management vulnerability related to io_uring and buffer cloning in the Linux kernel.
Is there any exploit available for CVE-2025-21686?
As of the current information, there are no publicly known exploits for CVE-2025-21686.

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