{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-99258", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.404Z", "datePublished": "2026-11-03T11:25:14.680Z", "dateUpdated": "2026-11-03T11:40:46.409Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-11-03T11:40:46.409Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index()\n\nhv_apicid_to_vp_index() currently uses the per-cpu hypercall input\nand output pages. This function is called when running in VTL2 and\nwhen running in an SEV-SNP CoCo VM with no paravisor. In the former\ncase, the output page is allocated, but in the latter case it is\nnot, so the hypervisor stores the output VP index in memory that has\nnot been allocated by the guest.\n\nFix this by using the input page for both input and output. The\nhypercall has very small input and output, so sharing the same\npage for both is straightforward. An alternative fix is to\nallocate the per-cpu output page when running in an SEV-SNP CoCo\nguest, but this uses significantly more memory, particularly\nwith larger vCPUs counts."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["arch/x86/hyperv/hv_init.c"], "versions": [{"version": "3d12349ade541eefde0e71bf5c4aa7aa04c52a79", "lessThan": "bdba5f1b8bd0d18b1df61f769b559ed272902489", "status": "affected", "versionType": "git"}, {"version": "86c48271e0d60c82665e9fd61277002391efcef7", "lessThan": "2b561786c9076a892ef8b8f416c9828bc87ed44f", "status": "affected", "versionType": "git"}, {"version": "86c48271e0d60c82665e9fd61277002391efcef7", "lessThan": "bc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9", "status": "affected", "versionType": "git"}, {"version": "86c48271e0d60c82665e9fd61277002391efcef7", "lessThan": "7b74c117e2aac78e0f723e1c9c3644451c56b0d9", "status": "affected", "versionType": "git"}, {"version": "cb002d6c8f06d6061e84b2109cb84416107a9fb9", "status": "affected", "versionType": "git"}, {"version": "6.12.41", "lessThan": "6.12.115", "status": "affected", "versionType": "semver"}, {"version": "6.15.3", "lessThan": "6.16", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["arch/x86/hyperv/hv_init.c"], "versions": [{"version": "6.16", "status": "affected"}, {"version": "0", "lessThan": "6.16", "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": "6.12.41", "versionEndExcluding": "6.12.115"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "6.18.59"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.2.13"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/bdba5f1b8bd0d18b1df61f769b559ed272902489"}, {"url": "https://git.kernel.org/stable/c/2b561786c9076a892ef8b8f416c9828bc87ed44f"}, {"url": "https://git.kernel.org/stable/c/bc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9"}, {"url": "https://git.kernel.org/stable/c/7b74c117e2aac78e0f723e1c9c3644451c56b0d9"}], "title": "x86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index()", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["arch/x86/hyperv/hv_init.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "bdba5f1b8bd0d18b1df61f769b559ed272902489", "status": "affected", "version": "3d12349ade541eefde0e71bf5c4aa7aa04c52a79", "versionType": "git"}, {"lessThan": "2b561786c9076a892ef8b8f416c9828bc87ed44f", "status": "affected", "version": "86c48271e0d60c82665e9fd61277002391efcef7", "versionType": "git"}, {"lessThan": "bc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9", "status": "affected", "version": "86c48271e0d60c82665e9fd61277002391efcef7", "versionType": "git"}, {"lessThan": "7b74c117e2aac78e0f723e1c9c3644451c56b0d9", "status": "affected", "version": "86c48271e0d60c82665e9fd61277002391efcef7", "versionType": "git"}, {"status": "affected", "version": "cb002d6c8f06d6061e84b2109cb84416107a9fb9", "versionType": "git"}, {"lessThan": "6.12.115", "status": "affected", "version": "6.12.41", "versionType": "semver"}, {"lessThan": "6.16", "status": "affected", "version": "6.15.3", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["arch/x86/hyperv/hv_init.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.16"}, {"lessThan": "6.16", "status": "unaffected", "version": "0", "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"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index()\n\nhv_apicid_to_vp_index() currently uses the per-cpu hypercall input\nand output pages. This function is called when running in VTL2 and\nwhen running in an SEV-SNP CoCo VM with no paravisor. In the former\ncase, the output page is allocated, but in the latter case it is\nnot, so the hypervisor stores the output VP index in memory that has\nnot been allocated by the guest.\n\nFix this by using the input page for both input and output. The\nhypercall has very small input and output, so sharing the same\npage for both is straightforward. An alternative fix is to\nallocate the per-cpu output page when running in an SEV-SNP CoCo\nguest, but this uses significantly more memory, particularly\nwith larger vCPUs counts."}], "id": "CVE-2026-99258", "lastModified": "2026-11-03T12:17:32.713", "metrics": {}, "published": "2026-11-03T12:17:32.713", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2b561786c9076a892ef8b8f416c9828bc87ed44f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7b74c117e2aac78e0f723e1c9c3644451c56b0d9"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/bc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/bdba5f1b8bd0d18b1df61f769b559ed272902489"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: kernel: hyperv: Memory corruption via unallocated hypercall output page", "id": "2565711", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2565711"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.1", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-787", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nx86/hyperv: Avoid using per-cpu output page in hv_apicid_to_vp_index()\nhv_apicid_to_vp_index() currently uses the per-cpu hypercall input\nand output pages. This function is called when running in VTL2 and\nwhen running in an SEV-SNP CoCo VM with no paravisor. In the former\ncase, the output page is allocated, but in the latter case it is\nnot, so the hypervisor stores the output VP index in memory that has\nnot been allocated by the guest.\nFix this by using the input page for both input and output. The\nhypercall has very small input and output, so sharing the same\npage for both is straightforward. An alternative fix is to\nallocate the per-cpu output page when running in an SEV-SNP CoCo\nguest, but this uses significantly more memory, particularly\nwith larger vCPUs counts.", "A flaw was found in the Linux kernel's Hyper-V subsystem. When operating in an AMD Secure Encrypted Virtualization-Secure Nested Paging (SEV-SNP) confidential virtual machine without a paravisor, the kernel fails to allocate an output buffer for hypervisor communication. Consequently, querying virtual processor information causes the hypervisor to write into unallocated guest memory, which can lead to memory corruption, system instability, or a Denial of Service (DoS)."], "name": "CVE-2026-99258", "package_state": [{"cpe": "cpe:/a:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:rhel_els:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:rhel_els:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:rhel_els:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/a:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/a:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/a:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:5", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-10", "product_name": "Red Hat OpenShift Container Platform 5"}, {"cpe": "cpe:/a:redhat:openshift:5", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 5"}], "public_date": "2026-11-03T11:25:14Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-99258\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-99258\nhttps://git.kernel.org/stable/c/2b561786c9076a892ef8b8f416c9828bc87ed44f\nhttps://git.kernel.org/stable/c/7b74c117e2aac78e0f723e1c9c3644451c56b0d9\nhttps://git.kernel.org/stable/c/bc8ca0f4769627ae7d04e7ffdbd20de4f27a9bf9\nhttps://git.kernel.org/stable/c/bdba5f1b8bd0d18b1df61f769b559ed272902489"], "threat_severity": "Moderate"}

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