CVE-2026-98125 smb/client: fix stale page cache in insert/collapse range

What is CVE-2026-98125?

CVE-2026-98125 is a medium-severity vulnerability in Linux kernel, published on 25 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

smb/client: fix stale page cache in insert/collapse range

smb3_insert_range() and smb3_collapse_range() use truncate_pagecache_range() to invalidate the affected page cache. However, if off or old_eof is not page-aligned, the boundary pages are only partially zeroed and remain uptodate. As a result, the client may return stale data after a successful insert/collapse range operation.

For example, with 4K pages:

page 0 page 1 page 2 0------4K 4K------8K 8K------12K ^ ^ off=2K old_eof=10K

Page 1 is removed from the page cache, while the boundary pages are only partially zeroed. After COPYCHUNK moves the data on the server, these cached pages may still return stale data.

This can be reproduced on a CIFS mount:

bash -c ' FILE=/mnt/scratch/repro

# Use a 6 KiB file so EOF is not page-aligned. dd if=/dev/urandom of=/tmp/src bs=1K count=6 status=none

# Expected: a 4 KiB hole followed by the original data. rm -f /tmp/expected truncate -s 4K /tmp/expected cat /tmp/src >> /tmp/expected

cp /tmp/src "$FILE"

# Prime the page cache before moving data on the server. cat "$FILE" > /dev/null

fallocate --insert-range -o 0 -l 4K "$FILE"

if cmp -s /tmp/expected "$FILE"; then echo "readback: OK" else echo "readback: STALE DATA" fi '

Fix this by writing back dirty data and discarding the page cache from the start of the page containing off to EOF before moving data on the server.

Weakness: CWE-669

Which versions are affected by CVE-2026-98125?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-98125?

Apply the vendor's patch.

Is CVE-2026-98125 being exploited?

There is no known exploitation of CVE-2026-98125 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-104277, BELL-CVE-2026-98125, DEBIAN-CVE-2026-98125, GHSA-mgrf-j38j-q2mg, UBUNTU-CVE-2026-98125.