Out-of-bounds Read Affecting kernel package, versions *


Severity

Recommended
medium

Based on CentOS security rating.

Threat Intelligence

EPSS
0.19% (8th percentile)

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  • Snyk IDSNYK-CENTOS10-KERNEL-20238422
  • published29 Sept 2026
  • disclosed25 Sept 2026

Introduced: 25 Sep 2026

NewCVE-2026-97563  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 kernel.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel package and not the kernel package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

smb: client: reject out-of-bounds DataOffset in CIFSSMBRead()

The SMB1 synchronous read helper CIFSSMBRead() validates the server's DataLength against CIFSMaxBufSize and the caller's count, but never validates DataOffset. The copy source is formed as

&pSMBr->hdr.Protocol + le16_to_cpu(pSMBr->DataOffset)

and memcpy()'d for DataLength bytes with no check that the [DataOffset, DataOffset + DataLength) range lies within the response actually received from the server.

A malicious or compromised SMB1 server can return a response carrying an in-range DataLength and a large DataOffset, driving the source pointer past the end of the response buffer. The memcpy() then copies adjacent kernel heap into the caller's read buffer (information disclosure), or reads unmapped memory and oopses (denial of service). SMB1 is not negotiated by default; reaching this code requires an explicit vers=1.0 mount.

Both DataOffset and the received response length recorded in rsp_iov.iov_len are relative to the start of the SMB header, so reject the response unless DataOffset + DataLength fits within that length, using overflow-safe arithmetic, before forming the source pointer. The response length has been validated by the previous patch, so the DataOffset and DataLength fields can be read safely here.

While here, make data_length unsigned. It holds a length derived from unsigned on-the-wire fields and is only ever compared against unsigned quantities; print it with %u accordingly, and add func to the cifs_dbg() calls in this function.

CVSS Base Scores

version 3.1