smb: client: validate the data area in SMB2_read()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-99272
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-07 14:17:02 UTC
Updated2026-11-07 14:17:02 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: smb: client: validate the data area in SMB2_read() SMB2_read() copies le32_to_cpu(rsp->DataLength) bytes from (char *)rsp + rsp->DataOffset without checking that the range lies within the response actually received. A READ response with DataOffset == 0 makes smb2_get_data_area_len() zero the data length, so smb2_check_message() accepts a frame as short as the fixed response, while SMB2_read() still uses the server-supplied DataLength, capped only by CIFS_MAX_MSGSIZE and the caller's length. A malicious server can answer the synchronous read used by the mfsymlinks (or SFU) symlink parser with an 81-byte READ response carrying DataOffset 0 and DataLength 1067, making the client copy 1067 bytes from a 448-byte receive object (KASAN slab-out-of-bounds; up to 16 KiB in the general case). Clamp a zero (or header-overlapping) DataOffset to read_rsp_size, as handle_read_data() does for the asynchronous path, and reject the response unless DataOffset + DataLength fits within rsp_iov.iov_len. The SMB1 helper was fixed the same way in 5be5bdda5863.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected d8e050398d23ef7c019c96200b80d73f4e5cec0c 1ba1937de005e261a8858f45bfef5da7458df94c git Not specified
CNA Linux Linux affected d8e050398d23ef7c019c96200b80d73f4e5cec0c 2ec9cdf469dd32bcf33073aeb30c08e9356e0ca1 git Not specified
CNA Linux Linux affected 3.7 Not specified
CNA Linux Linux unaffected 3.7 semver Not specified
CNA Linux Linux unaffected 7.3.2 7.3.* semver Not specified
CNA Linux Linux unaffected 7.4-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/2ec9cdf469dd32bcf33073aeb30c08e9356e0ca1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/1ba1937de005e261a8858f45bfef5da7458df94c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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