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Response snapshot Oct 27, 2026, 02:52 UTC

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VulnerabilityCVE-2026-98454

Linux kernel: smb: client: fix create context out-of-bounds reads

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix create context out-of-bounds reads smb2_parse_contexts() validates the complete create-context area but does not limit each record to its Next field before dispatching it.

Published Updated

At a glance

Exploited
Not known
Severity
8.1 High (CVSS 3.1)
Chance of exploitation
0.3% in the next 30 days
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-98454 (opens a new tab)

What happened

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

smb: client: fix create context out-of-bounds reads

smb2_parse_contexts() validates the complete create-context area but does not limit each record to its Next field before dispatching it. A malformed chain can therefore expose bytes beyond the current context to a handler. The QFid handler also used a full response-structure cast although it only reads DiskFileId.

The SMB2/SMB3 lease parsers made the same layout assumption: they read LeaseState and LeaseFlags at canonical offsets rather than at DataOffset. A valid non-canonical DataOffset could therefore yield unrelated in-bounds data, while a short DataLength was still accepted.

Continue reading

Limit each context to its Next value, reject offsets before the context header, and reject malformed chains. Bound the name range by the current context and do not dispatch a known handler when DataLength is zero. Read the QFid DiskFileId only when the context data covers that field. Parse the lease context from DataOffset and require DataLength to match the v1 or v2 lease_context size used by ksmbd. A size mismatch skips lease parsing without failing the open.

Scores and how they were measured

CVSS base severity

8.1

Version 3.1As of

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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

0.3%

Scored Percentile 27.7%

Model and measurement source (opens a new tab)

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-2026-98454 (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

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-98454, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

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

APA

KEVWire. (2026, October 24). Linux kernel: smb: client: fix create context out-of-bounds reads (CVE-2026-98454). https://kevwire.com/record/CVE-2026-98454

MLA

"Linux kernel: smb: client: fix create context out-of-bounds reads (CVE-2026-98454)." KEVWire, 24 Oct. 2026, kevwire.com/record/CVE-2026-98454.

Chicago

KEVWire. "Linux kernel: smb: client: fix create context out-of-bounds reads (CVE-2026-98454)." Last modified October 24, 2026. https://kevwire.com/record/CVE-2026-98454.

Evidence summary (plain text)

Linux kernel: smb: client: fix create context out-of-bounds reads (Oct 18, 2026).
In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix create context out-of-bounds reads

smb2_parse_contexts() validates the complete create-context area but
does not limit each record to its Next field before dispatching it.  A
malformed chain can therefore expose bytes beyond the current context to
a handler.  The QFid handler also used a full response-structure cast
although it only reads DiskFileId.

The SMB2/SMB3 lease parsers made the same layout assumption: they read
LeaseState and LeaseFlags at canonical offsets rather than at
DataOffset.  A valid non-canonical DataOffset could therefore yield
unrelated in-bounds data, while a short DataLength was still accepted.

Limit each context to its Next value, reject offsets before the context
header, and reject malformed chains.  Bound the name range by the current
context and do not dispatch a known handler when DataLength is zero.  Read
the QFid DiskFileId only when the context data covers that field.  Parse the
lease context from DataOffset and require DataLength to match the v1 or v2
lease_context size used by ksmbd.  A size mismatch skips lease parsing
without failing the open.
CVSS 8.1 (version 3.1; evidence as of Oct 24, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-98454).
EPSS 0.3% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-98454&date=2026-10-26).
Sources:
NVD CVE-2026-98454: https://nvd.nist.gov/vuln/detail/CVE-2026-98454
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?pubStartDate=2026-10-12T13:35:55.142Z&pubEndDate=2026-10-26T13:35:55.142Z&resultsPerPage=500&startIndex=4500
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-98454&date=2026-10-26
Record ID: CVE-2026-98454.
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 27, 2026, 01:40 UTC. Ingestion is not an independent editorial investigation.

NVD status: Received. 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

Record detail