CVE-2023-53100: 
Linux Kernel vulnerability analysis and mitigation

A vulnerability was discovered in the Linux kernel's ext4 filesystem implementation, identified as CVE-2023-53100. The issue was found by Syzbot and involves incorrect handling of inline data in the ext4updateinline_data function. The vulnerability was disclosed on May 2, 2025, affecting the Linux kernel's ext4 filesystem component (NVD).

The vulnerability occurs in the ext4updateinlinedata function where after ext4xattrshiftentries() is called, the iinlineoff value becomes incorrect (changes to 176 instead of the expected 164). This leads to an incorrect entry calculation, potentially causing 'free' to become negative. When ext4updateinline_data attempts to allocate memory using kzalloc() with an unsigned int len parameter, it may trigger a warning due to the large allocation size (Debian Tracker).

The vulnerability can trigger a kernel warning and potentially cause system instability. When exploited, it affects the ext4 filesystem's inline data handling mechanism, which could lead to memory allocation issues and potential system crashes (Red Hat).

The issue has been fixed by updating the 'iinlineoff' value after ext4xattrshiftentries() is called. The fix also removes unnecessary setting of EXT4STATEMAYINLINEDATA flag since ext4markinodedirty() already handles this appropriately. Fixed versions are available in various Linux distributions including Debian Bullseye (5.10.234-1), Bookworm (6.1.137-1), and Trixie/Sid (6.12.27-1) (Debian Tracker).