{"id":"CVE-2026-72310","state":"PUBLISHED","title":"smb: client: fix overflow in passthrough ioctl bounds check","description":"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.","publishedAt":"2026-08-15T05:55:26.539Z","updatedAt":"2026-10-16T18:55:16.690Z","severity":{"score":8.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"175357ee0c596cb82054650dfa32fda51ad35aaa","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"dbd126539c098dba3159ce7d34b10b2daddcbd0f","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"63feb687e89a3a52a31e6e01764117cc500f1974","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"160045fc943f6c46b227644261252c8a22b8a87a","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"b30771b69eafae750afb7385fbcc3d77ed3f3670","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"1627e7d5c9b09721a141d07cedb178882f1ded67","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"1a638c55f2db6cb2296e5e3138015dd8fd9d4aa9","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"a4f27ad055392fa164f5649e89a3637b033c5fcc","versionType":"git"},{"version":"2005c32ec99ee2490e8131b3953f3f212009ffea","status":"affected","versionType":"git"},{"version":"5.4.69","status":"affected","lessThan":"5.5","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/smb2ops.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.5","versionType":"semver"},{"version":"5.10.261","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/smb2ops.c"]}],"references":["https://git.kernel.org/stable/c/175357ee0c596cb82054650dfa32fda51ad35aaa","https://git.kernel.org/stable/c/dbd126539c098dba3159ce7d34b10b2daddcbd0f","https://git.kernel.org/stable/c/63feb687e89a3a52a31e6e01764117cc500f1974","https://git.kernel.org/stable/c/160045fc943f6c46b227644261252c8a22b8a87a","https://git.kernel.org/stable/c/b30771b69eafae750afb7385fbcc3d77ed3f3670","https://git.kernel.org/stable/c/1627e7d5c9b09721a141d07cedb178882f1ded67","https://git.kernel.org/stable/c/1a638c55f2db6cb2296e5e3138015dd8fd9d4aa9","https://git.kernel.org/stable/c/a4f27ad055392fa164f5649e89a3637b033c5fcc"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/72xxx/CVE-2026-72310.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72310","state":"PUBLISHED","datePublished":"2026-08-15T05:55:26.539Z","dateUpdated":"2026-10-16T18:55:16.690Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-09T03:40:39.918Z"},"containers":{"cna":{"title":"smb: client: fix overflow in passthrough ioctl bounds check","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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"175357ee0c596cb82054650dfa32fda51ad35aaa","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"dbd126539c098dba3159ce7d34b10b2daddcbd0f","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"63feb687e89a3a52a31e6e01764117cc500f1974","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"160045fc943f6c46b227644261252c8a22b8a87a","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"b30771b69eafae750afb7385fbcc3d77ed3f3670","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"1627e7d5c9b09721a141d07cedb178882f1ded67","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"1a638c55f2db6cb2296e5e3138015dd8fd9d4aa9","versionType":"git"},{"version":"2b1116bbe898aefdf584838448c6869f69851e0f","status":"affected","lessThan":"a4f27ad055392fa164f5649e89a3637b033c5fcc","versionType":"git"},{"version":"2005c32ec99ee2490e8131b3953f3f212009ffea","status":"affected","versionType":"git"},{"version":"5.4.69","status":"affected","lessThan":"5.5","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/smb2ops.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.5","versionType":"semver"},{"version":"5.10.261","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/smb2ops.c"]}],"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"}],"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."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T05:42:38.636Z"},"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"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-72310","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T18:46:23.070703Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T18:55:16.690Z"}}]}}}