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smb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path

Type: advisorySource: Official CVE List1 source record

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.

Announced Group revision 1
Original source ↗

CVE-2026-31708

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-31708

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "f5778c398713692a16150ae96e5c8270bab8399f",
        "lessThan": "e66bdc0704977ecee667a81d38255b579c2353d0",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f5778c398713692a16150ae96e5c8270bab8399f",
        "lessThan": "9e203dbb5402897c43130fb171a2617008a91f45",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f5778c398713692a16150ae96e5c8270bab8399f",
        "lessThan": "1dd757379997b71a328a4b591ffaf481acd0ead1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f5778c398713692a16150ae96e5c8270bab8399f",
        "lessThan": "a34d456934fe42e4da5d2cc07787bf418bee99c6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f5778c398713692a16150ae96e5c8270bab8399f",
        "lessThan": "ac2f14e4705d020f04e806efa0d49ab8dc2b145f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f5778c398713692a16150ae96e5c8270bab8399f",
        "lessThan": "078fae8f50adebb903ccf2252b44391324571e78",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f5778c398713692a16150ae96e5c8270bab8399f",
        "lessThan": "85fd46ee26a11841c670449508025965f61ce131",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f5778c398713692a16150ae96e5c8270bab8399f",
        "lessThan": "a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/smb/client/smb2ops.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.1"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.1",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.259",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.210",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.175",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.136",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.84",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.25",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.0.2",
        "versionType": "semver",
        "lessThanOrEqual": "7.0.*"
      },
      {
        "status": "unaffected",
        "version": "7.1",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/smb/client/smb2ops.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-31708

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#39986 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement

Revision history

  1. CVE-2026-31708 · Revision 1Source updated