CVE-2025-38364

/// Technical description

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

maple_tree: fix MA_STATE_PREALLOC flag in mas_preallocate()

Temporarily clear the preallocation flag when explicitly requesting

allocations. Pre-existing allocations are already counted against the

request through mas_node_count_gfp(), but the allocations will not happen

if the MA_STATE_PREALLOC flag is set. This flag is meant to avoid

re-allocating in bulk allocation mode, and to detect issues with

preallocation calculations.

The MA_STATE_PREALLOC flag should also always be set on zero allocations

so that detection of underflow allocations will print a WARN_ON() during

consumption.

User visible effect of this flaw is a WARN_ON() followed by a null pointer

dereference when subsequent requests for larger number of nodes is

ignored, such as the vma merge retry in mmap_region() caused by drivers

altering the vma flags (which happens in v6.6, at least)

/// 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