High 8.1Published May 1, 2026

CVE-2026-31708smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path

Updated under an hour ago (Oct 27, 2026, 4:23 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path smb2_ioctl_query_info() has two response-copy branches: PASSTHRU_FSCTL and the default QUERY_INFO path. The QUERY_INFO branch clamps qi.input_buffer_length to the server-reported OutputBufferLength and then copies qi.input_buffer_length bytes from qi_rsp->Buffer to userspace, but it never verifies that the flexible-array payload actually fits within rsp_iov[1].iov_len. A malicious server can return OutputBufferLength larger than the actual QUERY_INFO response, causing copy_to_user() to walk past the response buffer and expose adjacent kernel heap to userspace. Guard the QUERY_INFO copy with a bounds check on the actual Buffer payload. Use struct_size(qi_rsp, Buffer, qi.input_buffer_length) rather than an open-coded addition so the guard cannot overflow on 32-bit builds.

CVSS: 8.1 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
Weakness (CWE): CWE-125
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from f5778c398713692a16150ae96e5c8270bab8399f before e66bdc0704977ecee667a81d38255b579c2353d0; from f5778c398713692a16150ae96e5c8270bab8399f before 9e203dbb5402897c43130fb171a2617008a91f45; from f5778c398713692a16150ae96e5c8270bab8399f before 1dd757379997b71a328a4b591ffaf481acd0ead1; from f5778c398713692a16150ae96e5c8270bab8399f before a34d456934fe42e4da5d2cc07787bf418bee99c6; from f5778c398713692a16150ae96e5c8270bab8399f before ac2f14e4705d020f04e806efa0d49ab8dc2b145f; from f5778c398713692a16150ae96e5c8270bab8399f before 078fae8f50adebb903ccf2252b44391324571e78; from f5778c398713692a16150ae96e5c8270bab8399f before 85fd46ee26a11841c670449508025965f61ce131; from f5778c398713692a16150ae96e5c8270bab8399f before a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e	CNA record
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name)	all versions	CISA ADP
linux linux_kernel linux:linux_kernel	from 5.1 before 6.6.136; from 6.7 before 6.12.84; from 6.13 before 6.18.25; from 6.19 before 7.0.2	NVD

References

References

https://git.kernel.org/stable/c/e66bdc0704977ecee667a81d38255b579c2353d0
https://git.kernel.org/stable/c/9e203dbb5402897c43130fb171a2617008a91f45
https://git.kernel.org/stable/c/1dd757379997b71a328a4b591ffaf481acd0ead1
https://git.kernel.org/stable/c/a34d456934fe42e4da5d2cc07787bf418bee99c6	patch
https://git.kernel.org/stable/c/ac2f14e4705d020f04e806efa0d49ab8dc2b145f	patch
https://git.kernel.org/stable/c/078fae8f50adebb903ccf2252b44391324571e78	patch
https://git.kernel.org/stable/c/85fd46ee26a11841c670449508025965f61ce131	patch
https://git.kernel.org/stable/c/a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e	patch
https://cert-portal.siemens.com/productcert/html/ssa-784472.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.