CVE-2026-98373

What the bug is

move_hugetlb_page_tables() optimizes mremap() by advancing to the last entry in the page table when the source page table does not exist, either initially or after unsharing a PMD table. The common loop increment then steps to the first entry in the next page table. However, the code advances both the source and destination addresses to the last entries in their respective page tables, which is wrong. The destination address must be advanced only by the same amount as the source address. If the source and destination offsets within their page tables differ, the destination address can be advanced too far, causing follow-up issues. Fix this by advancing the destination address by the source advance distance. With a reproducer, we were able to trigger a kernel panic on x86-64. With this fix in place, we can no longer reproduce the issue.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

mm/hugetlb.c

What this is

HUGETLB SUBSYSTEMMAINTAINERS section matched on mm/hugetlb.c · linux-mm@kvack.org · Maintained

Check it on the machine

grep -w CONFIG_HUGETLBFS /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

• bookwormYnot built on armhf/armmp, armhf/rt/armmp
• trixieYnot built on armel/rpi, armhf/armmp, armhf/rt/armmp
• forky, sidYnot built on armhf/armmp

Y

built in where it is built at all; some flavours do not build it

Build switch

CONFIG_HUGETLBFS

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-10-07 (12 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.16%, higher than 4.4% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

mm

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
6.0	6.12.112	7a96b0f657c8
6.0	6.18.55	850cc4a84b36
6.0	7.2.9	480a39b0a12c
6.0	7.3	9bdad082d44b

Debian advisories