smb: client: validate absolute native symlink targets before NT fixups

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-98318
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-06 09:18:23 UTC
Updated2026-10-07 07:17:08 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: smb: client: validate absolute native symlink targets before NT fixups With symlinkroot unset, an absolute target is copied without conversion to an NT drive path. Later code still assumes an NT prefix is present when modifying the target and calculating the print name length. For "/ab", this causes two failures: sym[5] and path[5] are written past their allocations, and plen -= 2 * poff subtracts an assumed 8-byte prefix from a 6-byte UTF-16 target, wrapping u16 plen to 65534. That underflow causes another overflow: memcpy() copies 65534 bytes into a 24-byte buffer. A user with write access to a mounted share can trigger these bugs with default settings. Validate the NT drive prefix, including an ASCII drive letter, before accessing fixed offsets or subtracting the prefix length.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.001620000 probability, percentile 0.048460000 (date 2026-10-06)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 3363da82e02f1bddc54faa92ea430c6532e2cd2e 6913ff607c2bc8694193e1fcc40bf16d75f35f16 git Not specified
CNA Linux Linux affected 3363da82e02f1bddc54faa92ea430c6532e2cd2e 23c240d9509e15f72e4112fc95f0160ab32ec430 git Not specified
CNA Linux Linux affected b6ea7b6c6be65149ab6b8e37a9dd1671f76add1b git Not specified
CNA Linux Linux affected 6.15.6 6.16 semver Not specified
CNA Linux Linux affected 6.16 Not specified
CNA Linux Linux unaffected 6.16 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/23c240d9509e15f72e4112fc95f0160ab32ec430 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6913ff607c2bc8694193e1fcc40bf16d75f35f16 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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