smb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-89632
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-11 20:19:48 UTC
Updated2026-09-13 07:17:28 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: smb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr() reparse_buf_ptr() reads buf->ReparseDataLength before checking that count covers the full fixed header: buf = (struct reparse_data_buffer *)((u8 *)io + off); len = sizeof(*buf); /* 8 bytes */ rdlen = le16_to_cpu(buf->ReparseDataLength); /* offset 4, 2 bytes */ if (count < len || count < rdlen + len) /* check comes after */ struct reparse_data_buffer has ReparseDataLength at offset 4. If a server returns OutputCount < 6, the read at offset 4-5 reaches past the end of the received data. The off+count bounds against iov_len were already validated, but that does not protect against count being smaller than sizeof(*buf). Split the check: verify count >= sizeof(*buf) before reading ReparseDataLength, then verify count covers the data region.

Risk And Classification

Primary CVSS: v3.1 8.2 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.003180000 probability, percentile 0.246110000 (date 2026-09-14)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary8.2HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
3.1CNADECLARED8.2HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected a158bb66b1373866d9fd5997565a58a573085539 711cf71300d7992f450600df8864917d3538679f git Not specified
CNA Linux Linux affected a158bb66b1373866d9fd5997565a58a573085539 05f78e6cf34ea3a285053bd5999e08e8ac298bd5 git Not specified
CNA Linux Linux affected 6.6.32 7.2.4 semver Not specified
CNA Linux Linux affected 6.6.32 7.3-rc1 semver Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/05f78e6cf34ea3a285053bd5999e08e8ac298bd5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/711cf71300d7992f450600df8864917d3538679f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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