CVE-2025-68791 concerns a vulnerability in the Linux kernel's FUSE subsystem where the copy_finish function was missing in fuse-over-io-uring argument copies. This omission could lead to a reference count leak of payload pages during argument copying, potentially impacting system stability or resource management. The vulnerability was resolved by adding the missing copy_finish call. The fix is included in Linux kernel updates starting from version 6.17.0-1018.18 and corresponding Ubuntu package versions. The vendor advisory from Ubuntu confirms the availability of the patch and recommends updating and rebooting the system. The update involves an ABI change requiring recompilation of third-party kernel modules.

The vulnerability causes a reference count leak of payload pages in the FUSE subsystem during argument copying, which could lead to resource leaks and potential system instability. There is no indication of direct exploitation or active exploits in the wild. The impact is categorized as medium severity.

A patch is available and included in Linux kernel version 6.17.0-1018.18 and later, as well as corresponding Ubuntu package updates. Users should apply the standard system update and reboot to ensure the fix is active. Due to an ABI change in the kernel update, recompilation and reinstallation of all third-party kernel modules are necessary. If standard kernel metapackages are installed, the system upgrade will handle this automatically.