{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72278", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.916Z", "datePublished": "2026-08-15T05:54:59.698Z", "dateUpdated": "2026-08-17T05:42:13.824Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:42:13.824Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: nv: Re-translate VNCR before injecting abort\n\nKVM faults in the VNCR page with FOLL_WRITE whenever the guest aborts\nfor a write, similar to how a regular stage-2 mapping is handled. It is\nentirely possible that the guest reads from the VNCR before writing to\nit, in which case the PFN could only be read-only.\n\nInvalidate the VNCR TLB and re-fetch the translation upon taking a VNCR\nabort, allowing the host mapping to be faulted in for write the second\ntime around. Interestingly enough, this also satisfies the ordering\nrequirements of FEAT_ETS2/3 between descriptor updates and MMU faults." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H", "baseScore": 9.3, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:L - The flaw is reached only when an arm64 nested-KVM L1 hypervisor triggers VNCR_EL2 data aborts (ESR_ELx_EC_DABT_CUR with ESR_ELx_VNCR) handled via KVM_RUN through kvm_handle_vncr_abort(); no network, adjacent-radio, or physical-device path reaches this code.\nAC:L - An attacker controlling an L1 nested-hypervisor VM can reliably issue read-then-write VNCR accesses, remap the VNCR page, and force translation/permission faults; nested virt on arm64 cloud hosts is an attacker-selectable deployment, not an uncontrollable condition.\nPR:N - Exploitation requires no host root or init-namespace capabilities beyond running hypervisor code in a tenant KVM guest on an arm64 host with nested virtualization enabled; the attacker operates entirely from within their assigned VM, consistent with other arm64 KVM nested-virt CVE scoring.\nUI:N - No victim user or administrator action is required beyond the attacker operating their own nested-virtualization workload; VNCR faults, pseudo-TLB reuse, and repeated write triggers are fully attacker-driven from within the guest.\nS:C - Stale VNCR pseudo-TLB and fixmap state lets guest-controlled faults cause host KVM to map and access the wrong guest physical pages when emulating EL2 register state, crossing the guest-to-hypervisor security boundary beyond the guest's intended authority.\nC:H - Reusing a cached VNCR translation without re-walking guest page tables can make the host read unintended guest physical pages through the per-CPU fixmap during VNCR emulation, providing a stale-translation information-disclosure primitive across guest memory views.\nI:H - Without re-translation on write aborts, a writable host fixmap established under a stale read-only fault can let the hypervisor write nested EL2 register values into the wrong guest physical page, corrupting memory the VMM expected to isolate.\nA:H - Incorrect permission/external-abort injection on VNCR write faults after a prior read leaves nested hypervisors unable to progress and can drive tight host-side fault-handling loops, causing CPU exhaustion and denial of service to co-resident workloads." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/arm64/kvm/nested.c" ], "versions": [ { "version": "2a359e072596fcb2e9e85017a865e3618a2fe5b5", "lessThan": "ea7a76d7d614b5f82b4d0785f9af3550e860a71a", "status": "affected", "versionType": "git" }, { "version": "2a359e072596fcb2e9e85017a865e3618a2fe5b5", "lessThan": "0a5dd8cf4d58ea28da132c2097cd1c525302ac48", "status": "affected", "versionType": "git" }, { "version": "2a359e072596fcb2e9e85017a865e3618a2fe5b5", "lessThan": "bb645aa0a4caeaf7f9cd32e9a948594d434c1a8f", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/arm64/kvm/nested.c" ], "versions": [ { "version": "6.16", "status": "affected" }, { "version": "0", "lessThan": "6.16", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "6.16", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/ea7a76d7d614b5f82b4d0785f9af3550e860a71a" }, { "url": "https://git.kernel.org/stable/c/0a5dd8cf4d58ea28da132c2097cd1c525302ac48" }, { "url": "https://git.kernel.org/stable/c/bb645aa0a4caeaf7f9cd32e9a948594d434c1a8f" } ], "title": "KVM: arm64: nv: Re-translate VNCR before injecting abort", "x_generator": { "engine": "bippy-1.2.0" } } } }