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Linux Kernel dmaengine/pxa kzalloc_flex Double-Counts nb_desc, Overflowing the Allocation Size and Corrupting Kernel Memory

Last refreshed2026-10-10

Status: UPDATED  |  Advisory ID: CVE-2026-98324

Key Details

CVECVE-2026-98324
CVSS Score / Version7.8 (High) / CVSS v3.1
Updated2026-10-07
CVSS VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS Proseattack vector is local; attack complexity is low; privileges required is low; user interaction is none; scope is unchanged; confidentiality impact is high; integrity impact is high; availability impact is high.
Affected productsLinux Kernel

Affected Products, Subsystems & Sectors

VendorProductAffected VersionsPatch Status
LinuxLinux Kernel
SubsystemsOT Supporting Infrastructure
SectorsAll Sectors

What to Know

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

dmaengine: pxa: fix double counting of the hw descriptors

pxad_alloc_desc() was converted from

kzalloc(struct_size(sw_desc, hw_desc, nb_hw_desc), GFP_NOWAIT)

to kzalloc_flex(), which sets the __counted_by() counter sw_desc->nb_desc

itself - but only where the compiler has __builtin_counted_by_ref(), so

from gcc 15.1 or clang 22.1 on. The loop below it still increments

nb_desc, which makes it come out doubled there and correct elsewhere.

nb_desc is what pxad_free_desc() iterates over and what

set_updater_desc() indexes from, so set it explicitly and drop the

increment. The error path has to lower it to the number of descriptors

allocated so far, otherwise pxad_free_desc() would free entries that were

never allocated. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References

SourceReference
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2026-98324
CVEhttps://www.cve.org/CVERecord?id=CVE-2026-98324