CVE-2026-31448

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ext4: avoid infinite loops caused by residual data

On the mkdir/mknod path, when mapping logical blocks to physical blocks,

if inserting a new extent into the extent tree fails (in this example,

because the file system disabled the huge file feature when marking the

inode as dirty), ext4_ext_map_blocks() only calls ext4_free_blocks() to

reclaim the physical block without deleting the corresponding data in

the extent tree. This causes subsequent mkdir operations to reference

the previously reclaimed physical block number again, even though this

physical block is already being used by the xattr block. Therefore, a

situation arises where both the directory and xattr are using the same

buffer head block in memory simultaneously.

The above causes ext4_xattr_block_set() to enter an infinite loop about

"inserted" and cannot release the inode lock, ultimately leading to the

143s blocking problem mentioned in [1].

If the me

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References