CVE-2026-23161

/// Technical description

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

mm/shmem, swap: fix race of truncate and swap entry split

The helper for shmem swap freeing is not handling the order of swap

entries correctly. It uses xa_cmpxchg_irq to erase the swap entry, but it

gets the entry order before that using xa_get_order without lock

protection, and it may get an outdated order value if the entry is split

or changed in other ways after the xa_get_order and before the

xa_cmpxchg_irq.

And besides, the order could grow and be larger than expected, and cause

truncation to erase data beyond the end border. For example, if the

target entry and following entries are swapped in or freed, then a large

folio was added in place and swapped out, using the same entry, the

xa_cmpxchg_irq will still succeed, it's very unlikely to happen though.

To fix that, open code the Xarray cmpxchg and put the order retrieval and

value checking in the same critical section. Also, ensure the order won't

exceed

/// 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