In the Linux kernel, the following vulnerability has been resolved: ext4: don't enable large folios on encrypted inodes Commit 709f0f1f1bf5 ("ext4:… (CVE-2026-98941)

The Linux kernel ext4 filesystem had a vulnerability where large folios were enabled on encrypted inodes if the encrypt feature was enabled on a mounted filesystem, circumventing the intended check that disables large folios when the block size is greater than the page size. This caused a NULL pointer dereference kernel crash during writes to encrypted data. The fix disables large folios on encrypted inodes, aligning with existing behavior for data journaling inodes. This issue affects kernels from version 6.19 through 7.2 and is resolved in version 7.3 where the ext4 code was refactored.

Exploitation of this vulnerability causes a kernel crash (NULL pointer dereference) when writing encrypted data on ext4 filesystems with large folios enabled on encrypted inodes. This results in denial of service due to system instability or crash. There is no indication of privilege escalation or data corruption beyond the crash. No known exploits are reported in the wild.

A fix is available in Linux kernel version 7.3, which includes a refactored ext4 codebase that disables large folios on encrypted inodes. Users should upgrade to kernel version 7.3 or later to remediate this issue. For affected versions between 6.19 and 7.2, applying the patch that disables large folios on encrypted inodes is necessary. No additional mitigation steps are indicated.