smb: client: fix next_buffer UAF and NextCommand bounds in compound PDUs

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-98171
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-06 09:17:58 UTC
Updated2026-10-07 07:17:03 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: smb: client: fix next_buffer UAF and NextCommand bounds in compound PDUs Fix several related bounds checking and pointer lifecycle issues in receive_encrypted_standard()'s handling of compound encrypted frames: - Clear next_buffer after assigning it to server->bigbuf. A stale next_buffer pointer can lead to a use-after-free on subsequent error paths. - Update pdu_length to the decrypted plaintext size (buf_size). Using the pre-decryption length allows NextCommand to point into stale ciphertext residue. - Reject next_cmd values smaller than MID_HEADER_SIZE(server). - Fix an integer overflow in the upper bound check by verifying pdu_length - next_cmd < MID_HEADER_SIZE(server), ensuring the trailing slice is large enough for a header.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.002150000 probability, percentile 0.108120000 (date 2026-10-06)

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

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected b24df3e30cbf48255db866720fb71f14bf9d2f39 72eaef1f37a3b6bec11c342736834dc3707be3e4 git Not specified
CNA Linux Linux affected b24df3e30cbf48255db866720fb71f14bf9d2f39 491e33144dee872cffda207f6fcb09260728f803 git Not specified
CNA Linux Linux affected b24df3e30cbf48255db866720fb71f14bf9d2f39 8749946579708ea0d339034bb7f423a67dbe89cf git Not specified
CNA Linux Linux affected b24df3e30cbf48255db866720fb71f14bf9d2f39 96c436e4b010711452b2872558938f4ef276492a git Not specified
CNA Linux Linux affected b24df3e30cbf48255db866720fb71f14bf9d2f39 858d5ac22cb889266993e7670f9f0c4f4aeedd78 git Not specified
CNA Linux Linux affected b24df3e30cbf48255db866720fb71f14bf9d2f39 05762c5bc1cfdcac36747994fde2c04387a457f1 git Not specified
CNA Linux Linux affected 4.19 Not specified
CNA Linux Linux unaffected 4.19 semver Not specified
CNA Linux Linux unaffected 6.1.189 6.1.* 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 6.18.54 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.8 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc4 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/72eaef1f37a3b6bec11c342736834dc3707be3e4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/05762c5bc1cfdcac36747994fde2c04387a457f1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8749946579708ea0d339034bb7f423a67dbe89cf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/491e33144dee872cffda207f6fcb09260728f803 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/858d5ac22cb889266993e7670f9f0c4f4aeedd78 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/96c436e4b010711452b2872558938f4ef276492a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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