CVE-2026-45942

/// Technical description

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

ext4: fix e4b bitmap inconsistency reports

A bitmap inconsistency issue was observed during stress tests under

mixed huge-page workloads. Ext4 reported multiple e4b bitmap check

failures like:

ext4_mb_complex_scan_group:2508: group 350, 8179 free clusters as

per group info. But got 8192 blocks

Analysis and experimentation confirmed that the issue is caused by a

race condition between page migration and bitmap modification. Although

this timing window is extremely narrow, it is still hit in practice:

folio_lock ext4_mb_load_buddy

__migrate_folio

check ref count

folio_mc_copy __filemap_get_folio

folio_try_get(folio)

......

mb_mark_used

ext4_mb_unload_buddy

__folio_migrate_mapping

folio_ref_freeze

folio_unlock

The root cause o

/// 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