The vulnerability (CVE-2026-46094) in the Linux kernel ext4 filesystem is due to an incorrect bounds check in the check_xattrs() function. The original check (void *)next >= end allows the pointer 'next' to be positioned within sizeof(u32) bytes of the end boundary, which leads to an out-of-bounds read when IS_LAST_ENTRY() reads 4 bytes starting at 'next'. This can cause memory access beyond the valid xattr region. The fix changes the check to (void *)next + sizeof(u32) > end, ensuring the pointer does not approach the boundary too closely and preventing the out-of-bounds read. The vulnerability is classified under CWE-125 (Out-of-bounds Read).

The vulnerability allows an out-of-bounds read of 4 bytes beyond the valid extended attribute region in the ext4 filesystem code. This can lead to denial of service (application or system crash) due to memory corruption. Confidentiality impact is rated high as per the CVSS vector, indicating potential exposure of sensitive information from memory. Integrity impact is none, and availability impact is high due to possible crashes.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The vulnerability description indicates a fix by adjusting the bounds check in the Linux kernel ext4 code, but no explicit patch link or official fix advisory is provided. Users should monitor the Microsoft Security Response Center and Linux kernel advisories for an official patch and apply it once available. Until then, avoid untrusted input that could trigger extended attribute parsing in ext4 if possible.