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Response snapshot Oct 28, 2026, 17:16 UTC

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VulnerabilityCVE-2026-98118

Linux kernel: netfs: Fix readahead synchronisation issues by loading all folios upfront

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…

At a glance

Exploited
Not known
Severity
7.1 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-98118 (opens a new tab)

What happened

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.

Continue reading

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.

Scores and how they were measured

CVSS base severity

7.1

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-98118 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 28). Linux kernel: netfs: Fix readahead synchronisation issues by loading all folios upfront (CVE-2026-98118). https://kevwire.com/record/CVE-2026-98118

MLA

"Linux kernel: netfs: Fix readahead synchronisation issues by loading all folios upfront (CVE-2026-98118)." KEVWire, 28 Oct. 2026, kevwire.com/record/CVE-2026-98118.

Chicago

KEVWire. "Linux kernel: netfs: Fix readahead synchronisation issues by loading all folios upfront (CVE-2026-98118)." Last modified October 28, 2026. https://kevwire.com/record/CVE-2026-98118.

Evidence summary (plain text)

Linux kernel: netfs: Fix readahead synchronisation issues by loading all folios upfront (Sep 25, 2026).
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…
CVSS 7.1 (version 3.1; evidence as of Oct 28, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-98118).
Sources:
NVD CVE-2026-98118: https://nvd.nist.gov/vuln/detail/CVE-2026-98118
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T15:41:02.957Z&lastModEndDate=2026-10-28T17:10:56.768Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T15:10:58.350Z&lastModEndDate=2026-10-28T16:40:56.161Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T14:31:18.089Z&lastModEndDate=2026-10-28T16:10:57.523Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-98118.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 28, 2026, 17:10 UTC. Ingestion is not an independent editorial investigation.

NVD status: Analyzed. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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