{"id":"CVE-2026-31608","state":"PUBLISHED","title":"smb: server: avoid double-free in smb_direct_free_sendmsg after smb_direct_flush_send_list()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: server: avoid double-free in smb_direct_free_sendmsg after smb_direct_flush_send_list()\n\nsmb_direct_flush_send_list() already calls smb_direct_free_sendmsg(),\nso we should not call it again after post_sendmsg()\nmoved it to the batch list.","publishedAt":"2026-04-24T14:42:30.137Z","updatedAt":"2026-08-05T12:23:46.955Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5ef18a2e66f2f33fdac64437bddfb9fe6389fdc7","status":"affected","lessThan":"6968c91fab05b8fc4d6700e0cf34472bb422df25","versionType":"git"},{"version":"79242e7b6bc63efec28b7c235bc320806afce6c0","status":"affected","lessThan":"2ba03f46132b0d1a7bafb86e1ef61951a2254023","versionType":"git"},{"version":"34abd408c8ba24d7c97bd02ba874d8c714f49db1","status":"affected","lessThan":"830de6eeb9db4cb7e758201fb99328ef4ca4b032","versionType":"git"},{"version":"34abd408c8ba24d7c97bd02ba874d8c714f49db1","status":"affected","lessThan":"84ff995ae826aa6bbcc6c7b9ea569ff67c021d72","versionType":"git"},{"version":"6.18.11","status":"affected","lessThan":"6.18.24","versionType":"semver"},{"version":"6.19.1","status":"affected","lessThan":"6.19.14","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/transport_rdma.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.0","versionType":"semver"},{"version":"6.18.24","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.14","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0.1","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/transport_rdma.c"]}],"references":["https://git.kernel.org/stable/c/6968c91fab05b8fc4d6700e0cf34472bb422df25","https://git.kernel.org/stable/c/2ba03f46132b0d1a7bafb86e1ef61951a2254023","https://git.kernel.org/stable/c/830de6eeb9db4cb7e758201fb99328ef4ca4b032","https://git.kernel.org/stable/c/84ff995ae826aa6bbcc6c7b9ea569ff67c021d72"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31608.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31608","state":"PUBLISHED","datePublished":"2026-04-24T14:42:30.137Z","dateUpdated":"2026-08-05T12:23:46.955Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.122Z"},"containers":{"cna":{"title":"smb: server: avoid double-free in smb_direct_free_sendmsg after smb_direct_flush_send_list()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: server: avoid double-free in smb_direct_free_sendmsg after smb_direct_flush_send_list()\n\nsmb_direct_flush_send_list() already calls smb_direct_free_sendmsg(),\nso we should not call it again after post_sendmsg()\nmoved it to the batch list."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5ef18a2e66f2f33fdac64437bddfb9fe6389fdc7","status":"affected","lessThan":"6968c91fab05b8fc4d6700e0cf34472bb422df25","versionType":"git"},{"version":"79242e7b6bc63efec28b7c235bc320806afce6c0","status":"affected","lessThan":"2ba03f46132b0d1a7bafb86e1ef61951a2254023","versionType":"git"},{"version":"34abd408c8ba24d7c97bd02ba874d8c714f49db1","status":"affected","lessThan":"830de6eeb9db4cb7e758201fb99328ef4ca4b032","versionType":"git"},{"version":"34abd408c8ba24d7c97bd02ba874d8c714f49db1","status":"affected","lessThan":"84ff995ae826aa6bbcc6c7b9ea569ff67c021d72","versionType":"git"},{"version":"6.18.11","status":"affected","lessThan":"6.18.24","versionType":"semver"},{"version":"6.19.1","status":"affected","lessThan":"6.19.14","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/transport_rdma.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.0","versionType":"semver"},{"version":"6.18.24","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.14","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0.1","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/transport_rdma.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/6968c91fab05b8fc4d6700e0cf34472bb422df25"},{"url":"https://git.kernel.org/stable/c/2ba03f46132b0d1a7bafb86e1ef61951a2254023"},{"url":"https://git.kernel.org/stable/c/830de6eeb9db4cb7e758201fb99328ef4ca4b032"},{"url":"https://git.kernel.org/stable/c/84ff995ae826aa6bbcc6c7b9ea569ff67c021d72"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - SMB Direct in ksmbd is exposed over RDMA network listeners on SMB-related ports, and a remote RDMA-capable peer can reach the vulnerable send path. The affected subsystem is an in-kernel SMB server transport, so the defensible vector is Network.\nAC:L - The attacker can establish an SMB Direct connection, request immediate/credit responses, and induce send failure by controlling the peer connection state. Any timing involved is attacker-controlled and repeatable, so complexity is Low.\nPR:N - The vulnerable path is reachable after RDMA/SMB Direct transport negotiation and before SMB user authentication. No valid SMB session or credentials are required to trigger the lower transport credit/keepalive send path.\nUI:N - Exploitation only requires network interaction with the listening ksmbd SMB Direct service. No victim user action is needed.\nS:U - The corruption occurs within the kernel handling the ksmbd transport and impacts the same kernel security authority. This is not a VM escape, sandbox boundary crossing, or separate security scope.\nC:H - The bug is a kernel heap double-free of an SMB Direct send object, which can create use-after-free or overlapping-allocation conditions. Such memory corruption can reasonably be leveraged for kernel memory disclosure, so Confidentiality is High.\nI:H - A double-free in kernel heap/mempool state can be exploitable for controlled memory corruption and potentially control-flow or data modification. Following the higher-severity rule for memory corruption, Integrity is High.\nA:H - At minimum, the double-free can corrupt allocator state or trigger kernel warnings/oops/panic during send teardown. A remote unauthenticated peer can repeatedly trigger the condition, so Availability is High."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:23:46.955Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.11","versionEndExcluding":"6.18.24"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19.1","versionEndExcluding":"6.19.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.0.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}