CVE-2026-31708 (GCVE-0-2026-31708)

Vulnerability from cvelistv5 – Published: 2026-05-01 13:56 – Updated: 2026-05-03 05:45
VLAI?
Title
smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path
Summary
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.
Severity ?
8.1 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: f5778c398713692a16150ae96e5c8270bab8399f , < a34d456934fe42e4da5d2cc07787bf418bee99c6 (git)
Affected: f5778c398713692a16150ae96e5c8270bab8399f , < ac2f14e4705d020f04e806efa0d49ab8dc2b145f (git)
Affected: f5778c398713692a16150ae96e5c8270bab8399f , < 078fae8f50adebb903ccf2252b44391324571e78 (git)
Affected: f5778c398713692a16150ae96e5c8270bab8399f , < 85fd46ee26a11841c670449508025965f61ce131 (git)
Affected: f5778c398713692a16150ae96e5c8270bab8399f , < a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e (git)
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    Linux Linux Affected: 5.1
Unaffected: 0 , < 5.1 (semver)
Unaffected: 6.6.136 , ≤ 6.6.* (semver)
Unaffected: 6.12.84 , ≤ 6.12.* (semver)
Unaffected: 6.18.25 , ≤ 6.18.* (semver)
Unaffected: 7.0.2 , ≤ 7.0.* (semver)
Unaffected: 7.1-rc1 , ≤ * (original_commit_for_fix)
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}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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