CVE-2026-74591

Technical Description

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

mm/filemap: __filemap_add_folio() restore index before retrying

In __filemap_add_folio()'s split-a-conflict loop, xas_set_order() is

applied repeatedly: each application modifies xas.xa_index, rounding it

down according to the split_order attempted at that stage: and if all goes

as intended, it eventually (or immediately) converges on an

xas_try_split() to the required folio_order, with xas.xa_index now the

same as index: then xas_store() puts the new folio into the xarray there.

But if a new node was needed, and GFP_NOWAIT allocation did not get one,

the lock is dropped, xas_nomem() used to allocate, and sequence retried.

If (that part of) the xarray is unchanged when the lock is reacquired, no

problem. But what if the conflict was meanwhile resolved by another

thread (perhaps even doing the same thing, inserting a folio at that same

index)? Isn't there a danger of now putting our folio into the xarray at

an int

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