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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-98454
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-18 16:16:55 UTC
Updated2026-10-24 14:16:42 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 8.1 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary8.1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
3.1CNADECLARED8.1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected b8c32dbb0deb287a5fcb78251e4eae6c7275760d e4c49012708c917eafd9c27054b02d0f8b30fe64 git Not specified
CNA Linux Linux affected b8c32dbb0deb287a5fcb78251e4eae6c7275760d 28bc9a871799363afa3139e961a8e3684feb8704 git Not specified
CNA Linux Linux affected b8c32dbb0deb287a5fcb78251e4eae6c7275760d 05a7fd80024ff32b9b40ab1478bb172eeab1c386 git Not specified
CNA Linux Linux affected b8c32dbb0deb287a5fcb78251e4eae6c7275760d cecc5399987e73a528ce2b662eeb54af69163cbd git Not specified
CNA Linux Linux affected b8c32dbb0deb287a5fcb78251e4eae6c7275760d 67f4c1c6a1b51e203d986779299824d1c2c590a6 git Not specified
CNA Linux Linux affected 3.7 Not specified
CNA Linux Linux unaffected 3.7 semver Not specified
CNA Linux Linux unaffected 6.6.158 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.112 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.55 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.9 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/cecc5399987e73a528ce2b662eeb54af69163cbd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/67f4c1c6a1b51e203d986779299824d1c2c590a6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/05a7fd80024ff32b9b40ab1478bb172eeab1c386 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e4c49012708c917eafd9c27054b02d0f8b30fe64 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/28bc9a871799363afa3139e961a8e3684feb8704 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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