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

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

https://cvefeed.io/rssfeed/latest.atom / Fri, 05/01/2026 - 17:21
CVE ID :CVE-2026-31708
Published : May 1, 2026, 1:56 p.m. | 19 minutes ago
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.
Severity: 0.0 | NA
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