{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-3865","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2023-07-24T14:52:38.053Z","datePublished":"2025-08-16T13:27:56.403Z","dateUpdated":"2026-08-15T12:23:42.112Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-15T12:23:42.112Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix out-of-bound read in smb2_write\n\nksmbd_smb2_check_message doesn't validate hdr->NextCommand. If\n->NextCommand is bigger than Offset + Length of smb2 write, It will\nallow oversized smb2 write length. It will cause OOB read in smb2_write."}],"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 - ksmbd is an in-kernel SMB server reachable over TCP/445; the bug is triggered by crafting SMB2 WRITE request fields (NextCommand/Length) sent from a remote SMB client.\nAC:L - The attacker fully controls NextCommand and Length in the SMB2 header/PDU and can reliably pass ksmbd_smb2_check_message by making them agree, with no race or other conditions outside attacker control.\nPR:L - smb2_write requires a valid SMB session, tree connect to a writable share, and an open file handle with write access; guest/basic share credentials suffice, but this is not a pre-authentication path.\nUI:N - Exploitation requires only attacker-sent SMB traffic; no victim user action such as opening a file or mounting a share is needed.\nS:U - Impact is confined to the host kernel running ksmbd; the vulnerability does not cross a VM, IOMMU, or other security authority boundary by itself.\nC:H - Oversized Length with a forged NextCommand causes smb2_write to kernel_write attacker-chosen lengths of memory past the request buffer into a share file the attacker can then read back, leaking large amounts of kernel memory (documented up to 64KiB).\nI:N - This is an out-of-bounds read only; it does not corrupt kernel memory or provide a write primitive into kernel structures.\nA:H - A large read past the kvmalloc'd request buffer can touch unmapped memory and cause a kernel oops/panic, or otherwise disrupt the ksmbd worker path."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smb2misc.c"],"versions":[{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","lessThan":"3813eee5154d6a4c5875cb4444cb2b63bac8947f","status":"affected","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","lessThan":"c86211159bc3178b891e0d60e586a32c7b6a231b","status":"affected","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","lessThan":"58a9c41064df27632e780c5a3ae3e0e4284957d1","status":"affected","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","lessThan":"5fe7f7b78290638806211046a99f031ff26164e1","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smb2misc.c"],"versions":[{"version":"5.15","status":"affected"},{"version":"0","lessThan":"5.15","status":"unaffected","versionType":"semver"},{"version":"5.15.121","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.36","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.3.10","lessThanOrEqual":"6.3.*","status":"unaffected","versionType":"semver"},{"version":"6.4","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":"5.15","versionEndExcluding":"5.15.121"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.1.36"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.3.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.4"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/3813eee5154d6a4c5875cb4444cb2b63bac8947f"},{"url":"https://git.kernel.org/stable/c/c86211159bc3178b891e0d60e586a32c7b6a231b"},{"url":"https://git.kernel.org/stable/c/58a9c41064df27632e780c5a3ae3e0e4284957d1"},{"url":"https://git.kernel.org/stable/c/5fe7f7b78290638806211046a99f031ff26164e1"}],"title":"ksmbd: fix out-of-bound read in smb2_write","x_generator":{"engine":"bippy-1.2.0"}}}}