{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-99216", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.401Z", "datePublished": "2026-10-28T10:36:09.383Z", "dateUpdated": "2026-10-31T12:45:15.499Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-31T12:45:15.499Z" }, "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": { "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" }, "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/hv/connection.c", "drivers/hv/vmbus_drv.c" ], "versions": [ { "version": "74347a99e73ae00b8385f1209aaea193c670f901", "lessThan": "2939215d57bc8e4189290544fca78f3809ac3ef8", "status": "affected", "versionType": "git" }, { "version": "74347a99e73ae00b8385f1209aaea193c670f901", "lessThan": "a0ae955ba9a5067a157ebb8defb4a0a9cb1fc304", "status": "affected", "versionType": "git" }, { "version": "74347a99e73ae00b8385f1209aaea193c670f901", "lessThan": "deef3ab5129ae4c45662c957cdab3739eb047fb1", "status": "affected", "versionType": "git" }, { "version": "74347a99e73ae00b8385f1209aaea193c670f901", "lessThan": "2e5ffbf1e41abbf6e02ce28115107938f55ff646", "status": "affected", "versionType": "git" }, { "version": "74347a99e73ae00b8385f1209aaea193c670f901", "lessThan": "2732210132f92aca0622b5134027990a809279d5", "status": "affected", "versionType": "git" }, { "version": "74347a99e73ae00b8385f1209aaea193c670f901", "lessThan": "f47ce27af80b87cc684d5c12b65506af498ac7e5", "status": "affected", "versionType": "git" }, { "version": "74347a99e73ae00b8385f1209aaea193c670f901", "lessThan": "3195546a377c2d8d176d837e8baad5ce15d11195", "status": "affected", "versionType": "git" }, { "version": "74347a99e73ae00b8385f1209aaea193c670f901", "lessThan": "ec31dc39e835ccde0930daccece8c492d28282fc", "status": "affected", "versionType": "git" }, { "version": "5e059fc0f054309036d3f612bc8b0a502ca58545", "status": "affected", "versionType": "git" }, { "version": "9f38f7b46de0747c1909e8c557aa21715dce20c5", "status": "affected", "versionType": "git" }, { "version": "caeeb3787167c884b955404a7e669fd77f267e44", "status": "affected", "versionType": "git" }, { "version": "4.19.118", "lessThan": "4.20", "status": "affected", "versionType": "semver" }, { "version": "5.4.35", "lessThan": "5.5", "status": "affected", "versionType": "semver" }, { "version": "5.6.7", "lessThan": "5.7", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/hv/connection.c", "drivers/hv/vmbus_drv.c" ], "versions": [ { "version": "5.7", "status": "affected" }, { "version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.273", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.224", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.161", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.115", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.59", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.13", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "5.7", "versionEndExcluding": "5.10.273" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "5.15.224" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.1.191" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.6.161" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.12.115" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.18.59" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.2.13" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.3" }, { "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" } ] } ] } ], "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" } } } }