{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72310","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-09T03:40:39.918Z","datePublished":"2026-08-15T05:55:26.539Z","dateUpdated":"2026-08-17T05:42:38.636Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T05:42:38.636Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix overflow in passthrough ioctl bounds check\n\nsmb2_ioctl_query_info() validates the PASSTHRU_FSCTL response payload\nbefore copying it to userspace.\n\nThe payload offset and length both come from 32-bit fields. The bounds\ncheck currently adds OutputOffset and qi.input_buffer_length directly, so\nthe addition can wrap in 32-bit arithmetic before the result is compared\nagainst the response buffer length.\n\nA malicious server can use a large OutputOffset and a small OutputCount\nto make the wrapped sum pass the bounds check. The later copy_to_user()\nthen reads from io_rsp + OutputOffset, outside the response buffer.\n\nUse size_add() for the offset plus length check so overflow is treated as\nout of bounds."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":8.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - Exploitation requires processing a crafted SMB2 IOCTL response from a malicious SMB/CIFS server over TCP; the bug is in client-side parsing of attacker-controlled network protocol fields, not in a purely local code path.\nAC:L - A malicious server can reliably supply OutputOffset and OutputCount values that wrap the 32-bit bounds check and pass validation, deterministically triggering the out-of-bounds copy_to_user() without races or special victim state.\nPR:L - The PASSTHRU_FSCTL ioctl path requires CAP_SYS_ADMIN, which an unprivileged local user can obtain inside a user namespace and use to mount CIFS and issue CIFS_QUERY_INFO against an attacker-controlled server.\nUI:N - In the highest-impact scenario the attacker controls the full chain (user-namespace mount plus ioctl) and needs no separate victim action beyond their own exploitation steps.\nS:U - Impact is disclosure of kernel heap memory to the calling userspace process within the same kernel security authority; it does not cross VM, IOMMU, or sandbox boundaries.\nC:H - The integer overflow bypasses bounds checking so copy_to_user() reads qi.input_buffer_length bytes from io_rsp plus attacker-chosen OutputOffset outside the SMB response buffer, leaking adjacent kernel memory to userspace.\nI:N - The flaw is an out-of-bounds kernel read copied to userspace; it does not modify kernel memory, corrupt metadata, or provide a write or code-execution primitive.\nA:H - Reading far outside the allocated SMB response buffer can access unmapped kernel pages during copy_to_user(), causing a kernel fault, oops, or panic in addition to information disclosure."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/smb2ops.c"],"versions":[{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","lessThan":"175357ee0c596cb82054650dfa32fda51ad35aaa","status":"affected","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","lessThan":"dbd126539c098dba3159ce7d34b10b2daddcbd0f","status":"affected","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","lessThan":"63feb687e89a3a52a31e6e01764117cc500f1974","status":"affected","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","lessThan":"160045fc943f6c46b227644261252c8a22b8a87a","status":"affected","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","lessThan":"b30771b69eafae750afb7385fbcc3d77ed3f3670","status":"affected","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","lessThan":"1627e7d5c9b09721a141d07cedb178882f1ded67","status":"affected","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","lessThan":"1a638c55f2db6cb2296e5e3138015dd8fd9d4aa9","status":"affected","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","lessThan":"a4f27ad055392fa164f5649e89a3637b033c5fcc","status":"affected","versionType":"git"},{"version":"2005c32ec99ee2490e8131b3953f3f212009ffea","status":"affected","versionType":"git"},{"version":"5.4.69","lessThan":"5.5","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/smb2ops.c"],"versions":[{"version":"5.5","status":"affected"},{"version":"0","lessThan":"5.5","status":"unaffected","versionType":"semver"},{"version":"5.10.261","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.212","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.178","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.145","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.97","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.40","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.5","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5","versionEndExcluding":"5.10.261"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5","versionEndExcluding":"5.15.212"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.69"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/175357ee0c596cb82054650dfa32fda51ad35aaa"},{"url":"https://git.kernel.org/stable/c/dbd126539c098dba3159ce7d34b10b2daddcbd0f"},{"url":"https://git.kernel.org/stable/c/63feb687e89a3a52a31e6e01764117cc500f1974"},{"url":"https://git.kernel.org/stable/c/160045fc943f6c46b227644261252c8a22b8a87a"},{"url":"https://git.kernel.org/stable/c/b30771b69eafae750afb7385fbcc3d77ed3f3670"},{"url":"https://git.kernel.org/stable/c/1627e7d5c9b09721a141d07cedb178882f1ded67"},{"url":"https://git.kernel.org/stable/c/1a638c55f2db6cb2296e5e3138015dd8fd9d4aa9"},{"url":"https://git.kernel.org/stable/c/a4f27ad055392fa164f5649e89a3637b033c5fcc"}],"title":"smb: client: fix overflow in passthrough ioctl bounds check","x_generator":{"engine":"bippy-1.2.0"}}}}