{"id":"CVE-2026-31609","state":"PUBLISHED","title":"smb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush()\n\nsmbd_send_batch_flush() already calls smbd_free_send_io(),\nso we should not call it again after smbd_post_send()\nmoved it to the batch list.","publishedAt":"2026-04-24T14:42:30.797Z","updatedAt":"2026-10-19T18:56:00.237Z","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":"cca0526ef2344cab6944d7f441fc24e152da031b","status":"affected","lessThan":"a9940dcbe5cb92482c04efc7341039ddf7dbf607","versionType":"git"},{"version":"37b5c06956183b65e6808b509cf637632016cdf7","status":"affected","lessThan":"22b7c1c619d808aec4cad3dc42103345e370d107","versionType":"git"},{"version":"21538121efe6c8c5b51c742fa02cbe820bc48714","status":"affected","lessThan":"f9a162c2bbcd0ac85bd07c5b37cf20286048b65c","versionType":"git"},{"version":"21538121efe6c8c5b51c742fa02cbe820bc48714","status":"affected","lessThan":"27b7c3e916218b5eb2ee350211140e961bfc49be","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/client/smbdirect.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/client/smbdirect.c"]}],"references":["https://git.kernel.org/stable/c/a9940dcbe5cb92482c04efc7341039ddf7dbf607","https://git.kernel.org/stable/c/22b7c1c619d808aec4cad3dc42103345e370d107","https://git.kernel.org/stable/c/f9a162c2bbcd0ac85bd07c5b37cf20286048b65c","https://git.kernel.org/stable/c/27b7c3e916218b5eb2ee350211140e961bfc49be"],"weaknesses":["CWE-415"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31609.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31609","state":"PUBLISHED","datePublished":"2026-04-24T14:42:30.797Z","dateUpdated":"2026-10-19T18:56:00.237Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.122Z"},"containers":{"cna":{"title":"smb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush()\n\nsmbd_send_batch_flush() already calls smbd_free_send_io(),\nso we should not call it again after smbd_post_send()\nmoved it to the batch list."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cca0526ef2344cab6944d7f441fc24e152da031b","status":"affected","lessThan":"a9940dcbe5cb92482c04efc7341039ddf7dbf607","versionType":"git"},{"version":"37b5c06956183b65e6808b509cf637632016cdf7","status":"affected","lessThan":"22b7c1c619d808aec4cad3dc42103345e370d107","versionType":"git"},{"version":"21538121efe6c8c5b51c742fa02cbe820bc48714","status":"affected","lessThan":"f9a162c2bbcd0ac85bd07c5b37cf20286048b65c","versionType":"git"},{"version":"21538121efe6c8c5b51c742fa02cbe820bc48714","status":"affected","lessThan":"27b7c3e916218b5eb2ee350211140e961bfc49be","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/client/smbdirect.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/client/smbdirect.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/a9940dcbe5cb92482c04efc7341039ddf7dbf607"},{"url":"https://git.kernel.org/stable/c/22b7c1c619d808aec4cad3dc42103345e370d107"},{"url":"https://git.kernel.org/stable/c/f9a162c2bbcd0ac85bd07c5b37cf20286048b65c"},{"url":"https://git.kernel.org/stable/c/27b7c3e916218b5eb2ee350211140e961bfc49be"}],"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 - The vulnerable path is in the SMB client SMB Direct/RDMA transport and processes protocol events from a remote SMB Direct peer over the network.\nAC:L - A malicious peer can request immediate empty responses and then disrupt the RDMA connection to drive the post-send error path; the trigger is repeatable and does not depend on conditions outside attacker influence.\nPR:N - The attacker is the remote SMB Direct peer/server and does not need privileges on the vulnerable client system or authenticated local access.\nUI:N - In a reasonable deployment with an existing or automatically established SMB Direct mount, the remote peer can trigger the bug through protocol traffic and disconnect timing without further user action.\nS:U - The corruption occurs in the client kernel and impacts the same operating-system security authority, with no VM, IOMMU, or sandbox boundary crossing identified.\nC:H - This is a kernel heap double-free of an SMB Direct send object; as memory corruption, it can plausibly be shaped into use-after-free behavior and kernel memory disclosure.\nI:H - The double-free corrupts kernel allocator state for objects used in RDMA send handling and can plausibly be leveraged for arbitrary kernel memory modification or code execution.\nA:H - Even without full exploitation, the double-free can trigger allocator corruption, warnings, oops, panic, or connection teardown, causing high availability impact."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:23:48.014Z"},"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"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-31609","role":"CISA 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