CVE-2023-52566: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-52566 is a vulnerability in the Linux kernel's NILFS2 filesystem component, specifically in the nilfsgccachesubmitreaddata() function. The vulnerability was discovered in 2023 and involves a potential use-after-free condition that could occur during garbage collection operations (NVD, RedHat).

The vulnerability exists in the nilfsgccachesubmitreaddata() function where brelse(bh) is called to drop the reference count of bh when nilfsdattranslate() fails. If the reference count reaches zero and the owner page gets unlocked, the buffer head (bh) may be freed. However, the code then attempts to dereference bh->b_page to put the page, potentially leading to a use-after-free condition. The issue specifically occurs during garbage collection operations and requires specific conditions to be triggered (Kernel Commit).

The vulnerability's impact is limited as it only affects the NILFS2 filesystem's garbage collection functionality. The issue is not exploitable through normal filesystem operations, as it requires either modifications to the userland garbage collection library or direct calls to the GC ioctl (Kernel Commit).

The vulnerability has been patched by moving the buffer release operation (brelse) after unlocking and putting the page. The fix has been incorporated into various Linux distributions including Ubuntu and Red Hat Enterprise Linux (Ubuntu Notice, RedHat).