CVE-2026-23249

/// Technical description

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

xfs: check for deleted cursors when revalidating two btrees

The free space and inode btree repair functions will rebuild both btrees

at the same time, after which it needs to evaluate both btrees to

confirm that the corruptions are gone.

However, Jiaming Zhang ran syzbot and produced a crash in the second

xchk_allocbt call. His root-cause analysis is as follows (with minor

corrections):

In xrep_revalidate_allocbt(), xchk_allocbt() is called twice (first

for BNOBT, second for CNTBT). The cause of this issue is that the

first call nullified the cursor required by the second call.

Let's first enter xrep_revalidate_allocbt() via following call chain:

xfs_file_ioctl() ->

xfs_ioc_scrubv_metadata() ->

xfs_scrub_metadata() ->

`sc->ops->repair_eval(sc)` ->

xrep_revalidate_allocbt()

xchk_allocbt() is called twice in this function. In the first call:

/* Note that sc->sm->sm_type is XFS_SCRUB_TYPE_BNOPT now */

/// 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