Log in Start free

Vulnerability · Published May 1, 2026 · Assigned by Linux

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

High 8.1

In plain English

A high-severity out-of-bounds read in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 29% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.4%top 71.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.176-1DEBIAN-CVE-2026-31708
Debian:13linux6.12.85-1DEBIAN-CVE-2026-31708
Debian:14linux7.0.3-1DEBIAN-CVE-2026-31708
Ubuntu:22.04:LTSlinux5.15.0-198.208USN-8875-1
Ubuntu:22.04:LTSlinux5.15.0-198.208UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux6.8.0-136.136UBUNTU-CVE-2026-31708
Ubuntu:25.10linuxno fix listedUBUNTU-CVE-2026-31708
Ubuntu:26.04:LTSlinux7.0.0-27.27UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-aws5.15.0-1117.124UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-aws5.15.0-1117.124USN-8875-1
Ubuntu:24.04:LTSlinux-aws6.8.0-1061.64UBUNTU-CVE-2026-31708
Ubuntu:25.10linux-awsno fix listedUBUNTU-CVE-2026-31708
Ubuntu:26.04:LTSlinux-aws7.0.0-1008.8UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1061.64~22.04.1UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-azure5.15.0-1123.132USN-8875-1
Ubuntu:22.04:LTSlinux-azure5.15.0-1123.132UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-azure6.8.0-1063.71UBUNTU-CVE-2026-31708
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-31708
Ubuntu:26.04:LTSlinux-azure7.0.0-1010.10UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1063.71~22.04.1UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1122.131UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1122.131USN-8876-1
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1062.69UBUNTU-CVE-2026-31708
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-31708
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1009.9UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1062.69~22.04.1UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-gcp5.15.0-1118.128UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-gcp5.15.0-1118.128USN-8877-1
Ubuntu:24.04:LTSlinux-gcp6.8.0-1064.72UBUNTU-CVE-2026-31708
Ubuntu:25.10linux-gcpno fix listedUBUNTU-CVE-2026-31708
Ubuntu:26.04:LTSlinux-gcp7.0.0-1007.7UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1064.72~22.04.1UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-gke5.15.0-1113.119USN-8875-1
Ubuntu:22.04:LTSlinux-gke5.15.0-1113.119UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-gke6.8.0-1059.67UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1100.108UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1100.108USN-8875-1
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1046.50UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-136.136~22.04.1UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-28.28~24.04.1UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-ibm5.15.0-1111.115UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-ibm5.15.0-1111.115USN-8875-1
Ubuntu:24.04:LTSlinux-ibm6.8.0-1061.62UBUNTU-CVE-2026-31708
Ubuntu:26.04:LTSlinux-ibm7.0.0-1009.9UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1061.62~22.04.1UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1112.118UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1112.118USN-8875-1
Ubuntu:22.04:LTSlinux-kvm5.15.0-1109.114UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-kvm5.15.0-1109.114USN-8875-1
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-195.205USN-8875-1
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-195.205UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-136.136.2UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-136.136.2~22.04.1UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1112.113UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1112.113USN-8875-2
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1059.62UBUNTU-CVE-2026-31708
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1013.13UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1059.62~22.04.1UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1059.62.1UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1070.72UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1030.31UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1059.59UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-oracle5.15.0-1114.120USN-8875-1
Ubuntu:22.04:LTSlinux-oracle5.15.0-1114.120UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-oracle6.8.0-1058.61UBUNTU-CVE-2026-31708
Ubuntu:25.10linux-oracleno fix listedUBUNTU-CVE-2026-31708
Ubuntu:26.04:LTSlinux-oracle7.0.0-1007.7UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1058.61~22.04.1UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-raspi6.8.0-1061.65UBUNTU-CVE-2026-31708
Ubuntu:25.10linux-raspino fix listedUBUNTU-CVE-2026-31708
Ubuntu:26.04:LTSlinux-raspi7.0.0-1014.14UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-31708
Ubuntu:25.10linux-realtimeno fix listedUBUNTU-CVE-2026-31708
Ubuntu:26.04:LTSlinux-realtime7.0.0-27.27.1UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-31708
Ubuntu:25.10linux-riscvno fix listedUBUNTU-CVE-2026-31708
Ubuntu:26.04:LTSlinux-riscv7.0.0-27.27.1UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-136.136~22.04.3UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-vmware6.8.0-1008.8UBUNTU-CVE-2026-31708
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1033.34UBUNTU-CVE-2026-31708
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1080.84USN-8875-1
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1080.84UBUNTU-CVE-2026-31708

Affected products (as reported)

VendorProductVersions
Linux Linux f5778c398713692a16150ae96e5c8270bab8399f – before e66bdc0704977ecee667a81d38255b579c2353d0f5778c398713692a16150ae96e5c8270bab8399f – before 9e203dbb5402897c43130fb171a2617008a91f45f5778c398713692a16150ae96e5c8270bab8399f – before 1dd757379997b71a328a4b591ffaf481acd0ead1f5778c398713692a16150ae96e5c8270bab8399f – before a34d456934fe42e4da5d2cc07787bf418bee99c6f5778c398713692a16150ae96e5c8270bab8399f – before ac2f14e4705d020f04e806efa0d49ab8dc2b145ff5778c398713692a16150ae96e5c8270bab8399f – before 078fae8f50adebb903ccf2252b44391324571e78f5778c398713692a16150ae96e5c8270bab8399f – before 85fd46ee26a11841c670449508025965f61ce131f5778c398713692a16150ae96e5c8270bab8399f – before a58c5af19ff0d6f44f6e9fe31e33a2c92223f77e
Linux Linux 5.1

Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

References