CVE-2026-98118: netfs: Fix readahead synchronisation issues by loading all folios upfront

High 7.1 EPSS 0.1% Linux kernel

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix readahead synchronisation issues by loading all folios upfront There are some synchronisation issues that derive from the app thread adding more folios to the rolling buffer whilst the collector thread is looking at them or trying to clear them, such as determining the setting of front_folio_order when the next folio hasn't been added yet, The reason for the rolling buffer approach is that loading the buffer upfront and then dropping all the refs just acquired is quite a slow operation, and loading progressively allows some of the cost to be deferred until after at least some of the I/O is started. Instead, a better way is to load all the folios into the rolling buffer upfront - and then drop the refs later, once the I/O is in progress. (Even better would be for the refs not to be there at all.) Fix this by changing the rolling buffer loader to load all the folios selected by the VM for readahead upfront into the folio queue. The folio queue is allocated a batch worth at a time as we don't know how many folios are involved (the readahead_control struct, alas, has a page count, not a folio count). The folio refs acquired from readahead are then dropped in bulk once the first subrequest is dispatched as it's quite a slow operation. The collector waits for NETFS_RREQ_NEED_PUT_RA_REFS to be cleared so that it doesn't unlock folios before the xarray has been scanned for them. This simplifies the buffer handling later and isn't noticeably slower as the xarray doesn't need to be modified and the folios are all already pre-locked.

• CVE-2026-98118CVE identifier
• 7.1CVSS 3.1 base score (high)
• 0.1%EPSS: chance of exploitation in the next 30 days (higher than 0% of CVEs)
• 2026-09-25published

What do these terms mean? CVE · CVSS score · exploited (KEV) · EPSS · backported fix · all terms

Affected and fixed versions

Affected:

• Linux Linux ee4cdf7ba857a894ad1650d6ab77669cbbfa329e to before 8c9b33945712074a85d3bdacbca036ba6b3d92c6
• Linux Linux ee4cdf7ba857a894ad1650d6ab77669cbbfa329e to before fed0b33e6c584986ba70018ec9f9787a98216e64
• Linux Linux 6.12

Patch it

Use the commands for your system. Distribution packages often keep an older version number with the fix backported, so compare with the fixed package versions in the table below, not only with the upstream version.

sudo apt update
sudo apt install --only-upgrade linux-image-amd64

sudo apt update
sudo apt install --only-upgrade linux-image-generic (or the installed flavour: linux-image-aws, -azure, -gcp, -virtual)

sudo dnf upgrade --refresh kernel

sudo dnf upgrade --refresh kernel

sudo zypper refresh
sudo zypper update kernel-default

sudo dnf upgrade --releasever=latest kernel kernel6.12

sudo pacman -Syu

apk update && apk upgrade linux-lts linux-virt

not Linux

General update steps for every system are on the Linux and Unix & BSD pages; after updating, see which services to restart.

Fix status in Linux distributions

From the Debian security tracker, Ubuntu CVE tracker and Red Hat Security Data API, refreshed every few hours.

Sources

• https://git.kernel.org/stable/c/8c9b33945712074a85d3bdacbca036ba6b3d92c6
• https://git.kernel.org/stable/c/fed0b33e6c584986ba70018ec9f9787a98216e64
• CVE-2026-98118 on CVE.org
• CVE-2026-98118 on NVD

Page generated automatically from official sources on 2026-11-03 18:05 UTC. Always confirm with your vendor's advisory.