{"api_version":"1","generated_at":"2026-11-01T09:41:03+00:00","cve":"CVE-2026-99216","urls":{"html":"https://cve.report/CVE-2026-99216","api":"https://cve.report/api/cve/CVE-2026-99216.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-99216","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-99216"},"summary":{"title":"Drivers: hv: Don't reset VMBus connection state on error/exit paths","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nDrivers: hv: Don't reset VMBus connection state on error/exit paths\n\nIn two places, current code forces vmbus_connection.conn_state to\nDISCONNECTED prior to calling vmbus_disconnect(). But vmbus_disconnect()\ncalls vmbus_initiate_unload(), which unloads the VMBus connection\nonly if the conn_state is CONNECTED. Consequently, the connection\nremains and the Hyper-V host might continue to send messages or post\nVMBus interrupts.\n\nThe problem was introduced in commit 74347a99e73ae (\"x86/Hyper-V:\nUnload vmbus channel in hv panic callback\"), in that\nvmbus_initiate_unload() started checking the current connection\nstate before doing the unload. This commit removed some occurrences\nwhere conn_state was forced to DISCONNECTED, but these two remained,\napparently due to an oversight at the time.\n\nFix this by not forcing conn_state to DISCONNECTED during VMBus exit,\nor if a failure occurs when establishing the connection in the first\nplace. Whatever value conn_state has at the time is then read by\nvmbus_initiate_unload() to determine if there is a connection to\nbe unloaded.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-28 11:17:43","updated_at":"2026-10-31 13:17:59"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"8.4","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.4,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.4","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":8.4,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/2e5ffbf1e41abbf6e02ce28115107938f55ff646","name":"https://git.kernel.org/stable/c/2e5ffbf1e41abbf6e02ce28115107938f55ff646","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a0ae955ba9a5067a157ebb8defb4a0a9cb1fc304","name":"https://git.kernel.org/stable/c/a0ae955ba9a5067a157ebb8defb4a0a9cb1fc304","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3195546a377c2d8d176d837e8baad5ce15d11195","name":"https://git.kernel.org/stable/c/3195546a377c2d8d176d837e8baad5ce15d11195","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/deef3ab5129ae4c45662c957cdab3739eb047fb1","name":"https://git.kernel.org/stable/c/deef3ab5129ae4c45662c957cdab3739eb047fb1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f47ce27af80b87cc684d5c12b65506af498ac7e5","name":"https://git.kernel.org/stable/c/f47ce27af80b87cc684d5c12b65506af498ac7e5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ec31dc39e835ccde0930daccece8c492d28282fc","name":"https://git.kernel.org/stable/c/ec31dc39e835ccde0930daccece8c492d28282fc","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2732210132f92aca0622b5134027990a809279d5","name":"https://git.kernel.org/stable/c/2732210132f92aca0622b5134027990a809279d5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2939215d57bc8e4189290544fca78f3809ac3ef8","name":"https://git.kernel.org/stable/c/2939215d57bc8e4189290544fca78f3809ac3ef8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-99216","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99216","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 74347a99e73ae00b8385f1209aaea193c670f901 2939215d57bc8e4189290544fca78f3809ac3ef8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 74347a99e73ae00b8385f1209aaea193c670f901 a0ae955ba9a5067a157ebb8defb4a0a9cb1fc304 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 74347a99e73ae00b8385f1209aaea193c670f901 deef3ab5129ae4c45662c957cdab3739eb047fb1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 74347a99e73ae00b8385f1209aaea193c670f901 2e5ffbf1e41abbf6e02ce28115107938f55ff646 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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caeeb3787167c884b955404a7e669fd77f267e44 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.19.118 4.20 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.4.35 5.5 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.6.7 5.7 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.7","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.7 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.273 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.224 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.191 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.161 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.115 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.59 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.13 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"99216","cve":"CVE-2026-99216","epss":"0.001710000","percentile":"0.064400000","score_date":"2026-10-31","updated_at":"2026-11-01 00:01:49"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/hv/connection.c","drivers/hv/vmbus_drv.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"2939215d57bc8e4189290544fca78f3809ac3ef8","status":"affected","version":"74347a99e73ae00b8385f1209aaea193c670f901","versionType":"git"},{"lessThan":"a0ae955ba9a5067a157ebb8defb4a0a9cb1fc304","status":"affected","version":"74347a99e73ae00b8385f1209aaea193c670f901","versionType":"git"},{"lessThan":"deef3ab5129ae4c45662c957cdab3739eb047fb1","status":"affected","version":"74347a99e73ae00b8385f1209aaea193c670f901","versionType":"git"},{"lessThan":"2e5ffbf1e41abbf6e02ce28115107938f55ff646","status":"affected","version":"74347a99e73ae00b8385f1209aaea193c670f901","versionType":"git"},{"lessThan":"2732210132f92aca0622b5134027990a809279d5","status":"affected","version":"74347a99e73ae00b8385f1209aaea193c670f901","versionType":"git"},{"lessThan":"f47ce27af80b87cc684d5c12b65506af498ac7e5","status":"affected","version":"74347a99e73ae00b8385f1209aaea193c670f901","versionType":"git"},{"lessThan":"3195546a377c2d8d176d837e8baad5ce15d11195","status":"affected","version":"74347a99e73ae00b8385f1209aaea193c670f901","versionType":"git"},{"lessThan":"ec31dc39e835ccde0930daccece8c492d28282fc","status":"affected","version":"74347a99e73ae00b8385f1209aaea193c670f901","versionType":"git"},{"status":"affected","version":"5e059fc0f054309036d3f612bc8b0a502ca58545","versionType":"git"},{"status":"affected","version":"9f38f7b46de0747c1909e8c557aa21715dce20c5","versionType":"git"},{"status":"affected","version":"caeeb3787167c884b955404a7e669fd77f267e44","versionType":"git"},{"lessThan":"4.20","status":"affected","version":"4.19.118","versionType":"semver"},{"lessThan":"5.5","status":"affected","version":"5.4.35","versionType":"semver"},{"lessThan":"5.7","status":"affected","version":"5.6.7","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/hv/connection.c","drivers/hv/vmbus_drv.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.7"},{"lessThan":"5.7","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.273","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.224","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.191","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.161","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.115","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.59","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.13","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.273","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.224","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.191","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.161","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.115","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.59","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.13","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.19.118","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.35","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6.7","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nDrivers: hv: Don't reset VMBus connection state on error/exit paths\n\nIn two places, current code forces vmbus_connection.conn_state to\nDISCONNECTED prior to calling vmbus_disconnect(). But vmbus_disconnect()\ncalls vmbus_initiate_unload(), which unloads the VMBus connection\nonly if the conn_state is CONNECTED. Consequently, the connection\nremains and the Hyper-V host might continue to send messages or post\nVMBus interrupts.\n\nThe problem was introduced in commit 74347a99e73ae (\"x86/Hyper-V:\nUnload vmbus channel in hv panic callback\"), in that\nvmbus_initiate_unload() started checking the current connection\nstate before doing the unload. This commit removed some occurrences\nwhere conn_state was forced to DISCONNECTED, but these two remained,\napparently due to an oversight at the time.\n\nFix this by not forcing conn_state to DISCONNECTED during VMBus exit,\nor if a failure occurs when establishing the connection in the first\nplace. Whatever value conn_state has at the time is then read by\nvmbus_initiate_unload() to determine if there is a connection to\nbe unloaded."}],"metrics":[{"cvssV3_1":{"baseScore":8.4,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - The attacker-controlled CHANNELMSG_VERSION_RESPONSE reaches vmbus_connect() through sysvec_hyperv_callback, vmbus_isr(), vmbus_on_msg_dpc(), and vmbus_onversion_response(); this is local Hyper-V IPC, not a network or physical protocol.\nAC:L - A backend can reject versions through 5.2, accept 5.1 in an isolation guest, then post rescind messages while the patched vmbus_connect() cleanup destroys its queues. The same backend controls both the state setup and racing messages.\nPR:N - vmbus_onversion_response() accepts the Hyper-V parent's VERSION_RESPONSE from the SynIC message page without guest credentials, capabilities, or authentication; the backend needs no privilege inside the guest.\nUI:N - hv_acpi_init() automatically calls vmbus_bus_init(), vmbus_alloc_synic_and_connect(), and vmbus_connect() during driver initialization; the backend supplies the responses without any victim action.\nS:U - The stale rescind_work_queue/work_queue accesses and resulting corruption occur within the same guest kernel that contains the vulnerable VMBus driver; no guest-to-host escape or IOMMU boundary bypass is produced.\nC:H - Without CHANNELMSG_UNLOAD, __vmbus_on_msg_dpc() can queue a rescind through a workqueue already RCU-freed by vmbus_disconnect(); this kernel heap use-after-free permits object reuse and guest-kernel memory disclosure.\nI:H - queue_work() dereferences the freed workqueue's cpu_pwq and updates pool counters and work-list state, so reuse of that storage can turn continued host messages into kernel heap writes and control-flow corruption.\nA:H - Continued rescind or offer messages can make __queue_work() access a destroyed or freed workqueue before hv_synic_cleanup() disables the SynIC, causing a warning, invalid-pointer fault, kernel oops, or panic."}]}],"providerMetadata":{"dateUpdated":"2026-10-31T12:45:15.499Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/2939215d57bc8e4189290544fca78f3809ac3ef8"},{"url":"https://git.kernel.org/stable/c/a0ae955ba9a5067a157ebb8defb4a0a9cb1fc304"},{"url":"https://git.kernel.org/stable/c/deef3ab5129ae4c45662c957cdab3739eb047fb1"},{"url":"https://git.kernel.org/stable/c/2e5ffbf1e41abbf6e02ce28115107938f55ff646"},{"url":"https://git.kernel.org/stable/c/2732210132f92aca0622b5134027990a809279d5"},{"url":"https://git.kernel.org/stable/c/f47ce27af80b87cc684d5c12b65506af498ac7e5"},{"url":"https://git.kernel.org/stable/c/3195546a377c2d8d176d837e8baad5ce15d11195"},{"url":"https://git.kernel.org/stable/c/ec31dc39e835ccde0930daccece8c492d28282fc"}],"title":"Drivers: hv: Don't reset VMBus connection state on error/exit paths","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-99216","datePublished":"2026-10-28T10:36:09.383Z","dateReserved":"2026-09-25T10:25:14.401Z","dateUpdated":"2026-10-31T12:45:15.499Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-28 11:17:43","lastModifiedDate":"2026-10-31 13:17:59","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.4,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2.5,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"99216","Ordinal":"1","Title":"Drivers: hv: Don't reset VMBus connection state on error/exit pa","CVE":"CVE-2026-99216","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"99216","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nDrivers: hv: Don't reset VMBus connection state on error/exit paths\n\nIn two places, current code forces vmbus_connection.conn_state to\nDISCONNECTED prior to calling vmbus_disconnect(). But vmbus_disconnect()\ncalls vmbus_initiate_unload(), which unloads the VMBus connection\nonly if the conn_state is CONNECTED. Consequently, the connection\nremains and the Hyper-V host might continue to send messages or post\nVMBus interrupts.\n\nThe problem was introduced in commit 74347a99e73ae (\"x86/Hyper-V:\nUnload vmbus channel in hv panic callback\"), in that\nvmbus_initiate_unload() started checking the current connection\nstate before doing the unload. This commit removed some occurrences\nwhere conn_state was forced to DISCONNECTED, but these two remained,\napparently due to an oversight at the time.\n\nFix this by not forcing conn_state to DISCONNECTED during VMBus exit,\nor if a failure occurs when establishing the connection in the first\nplace. Whatever value conn_state has at the time is then read by\nvmbus_initiate_unload() to determine if there is a connection to\nbe unloaded.","Type":"Description","Title":"Drivers: hv: Don't reset VMBus connection state on error/exit pa"}]}}}