{"api_version":"1","generated_at":"2026-09-08T03:21:09+00:00","cve":"CVE-2026-64555","urls":{"html":"https://cve.report/CVE-2026-64555","api":"https://cve.report/api/cve/CVE-2026-64555.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64555","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64555"},"summary":{"title":"KVM: arm64: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops()\n\nkvm_hyp_handle_mops() resets the single-step state machine as part of\nrewinding state for a MOPS exception by modifying vcpu_cpsr() and\nwriting the result directly into hardware.\n\nIn the case of nested virtualization, vcpu_cpsr() is a synthetic value\nsuch that the rest of KVM can deal with vEL2 cleanly. That means the\nvalue requires translation before being written into hardware, which is\nunfortunately missing from the MOPS handler.\n\nFix it by directly modifying SPSR_EL2 and avoiding the synthetic state\naltogether, which will be resynchronized on the next 'full' exit back\nto KVM.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-27 21:17:08","updated_at":"2026-08-17 05:18:01"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"8.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","data":{"baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/dd3b237eb7780d65eae296d3d3a70012b6e7a02f","name":"https://git.kernel.org/stable/c/dd3b237eb7780d65eae296d3d3a70012b6e7a02f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ff1022c3de46753eb7eba2f6efd990569e66ff95","name":"https://git.kernel.org/stable/c/ff1022c3de46753eb7eba2f6efd990569e66ff95","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/884b44256041ec6b2dcbe8e6a67384d26145cba1","name":"https://git.kernel.org/stable/c/884b44256041ec6b2dcbe8e6a67384d26145cba1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/10a568010e827108d149779908850afaec898846","name":"https://git.kernel.org/stable/c/10a568010e827108d149779908850afaec898846","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64555","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64555","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2de451a329cf662beeba71f63c7f83ee24ca6642 10a568010e827108d149779908850afaec898846 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2de451a329cf662beeba71f63c7f83ee24ca6642 884b44256041ec6b2dcbe8e6a67384d26145cba1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2de451a329cf662beeba71f63c7f83ee24ca6642 dd3b237eb7780d65eae296d3d3a70012b6e7a02f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2de451a329cf662beeba71f63c7f83ee24ca6642 ff1022c3de46753eb7eba2f6efd990569e66ff95 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.7","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.7 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.97 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.40 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64555","cve":"CVE-2026-64555","epss":"0.001280000","percentile":"0.029180000","score_date":"2026-08-17","updated_at":"2026-08-18 00:11:48"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["arch/arm64/kvm/hyp/include/hyp/switch.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"10a568010e827108d149779908850afaec898846","status":"affected","version":"2de451a329cf662beeba71f63c7f83ee24ca6642","versionType":"git"},{"lessThan":"884b44256041ec6b2dcbe8e6a67384d26145cba1","status":"affected","version":"2de451a329cf662beeba71f63c7f83ee24ca6642","versionType":"git"},{"lessThan":"dd3b237eb7780d65eae296d3d3a70012b6e7a02f","status":"affected","version":"2de451a329cf662beeba71f63c7f83ee24ca6642","versionType":"git"},{"lessThan":"ff1022c3de46753eb7eba2f6efd990569e66ff95","status":"affected","version":"2de451a329cf662beeba71f63c7f83ee24ca6642","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["arch/arm64/kvm/hyp/include/hyp/switch.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.7"},{"lessThan":"6.7","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.97","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.40","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.97","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.40","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"6.7","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops()\n\nkvm_hyp_handle_mops() resets the single-step state machine as part of\nrewinding state for a MOPS exception by modifying vcpu_cpsr() and\nwriting the result directly into hardware.\n\nIn the case of nested virtualization, vcpu_cpsr() is a synthetic value\nsuch that the rest of KVM can deal with vEL2 cleanly. That means the\nvalue requires translation before being written into hardware, which is\nunfortunately missing from the MOPS handler.\n\nFix it by directly modifying SPSR_EL2 and avoiding the synthetic state\naltogether, which will be resynchronized on the next 'full' exit back\nto KVM."}],"metrics":[{"cvssV3_1":{"baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - The attacker must be executing code inside a KVM/arm64 guest on the affected host — reached via /dev/kvm and guest instruction execution, not over any network protocol. This is local access to the host machine.\nAC:L - A guest hypervisor at vEL2 triggers the MOPS exception at will by executing a main/epilogue MOPS instruction with ill-formed alignment/size parameters; there is no race and no dependence on CPU migration or single-step state, so corruption of hardware SPSR_EL2 is fully deterministic.\nPR:L - Exploitation only needs the ability to create and run a nested-capable VM (/dev/kvm access, typically granted to unprivileged tenants/kvm-group users) and to run code inside that guest's own EL2 — no privilege on the host itself.\nUI:N - The guest triggers the faulty exception path entirely on its own during normal vCPU execution; no host user or administrator action is involved.\nS:C - The bogus ERET lands the guest's PC at real EL2 under the host's own EL2 translation regime and stack, with stage-2 no longer applied — the impact crosses the guest/host virtualization boundary into a different security authority.\nC:H - Execution at EL2 with the host's TTBR0_EL2/TTBR1_EL2 active and guest-controlled registers gives read access to the entire host kernel address space and to other guests' memory.\nI:H - The guest obtains a controlled control-flow transfer into host kernel text at EL2 with all GPRs under its control, which is an arbitrary code execution / arbitrary write primitive against the host hypervisor.\nA:H - Even without successful exploitation, ERETing to an unmapped or non-executable address at EL2 takes an unexpected EL2 exception that ends in a hyp panic, bringing down the host and every VM on it."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T04:57:33.289Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/10a568010e827108d149779908850afaec898846"},{"url":"https://git.kernel.org/stable/c/884b44256041ec6b2dcbe8e6a67384d26145cba1"},{"url":"https://git.kernel.org/stable/c/dd3b237eb7780d65eae296d3d3a70012b6e7a02f"},{"url":"https://git.kernel.org/stable/c/ff1022c3de46753eb7eba2f6efd990569e66ff95"}],"title":"KVM: arm64: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64555","datePublished":"2026-07-27T20:10:42.259Z","dateReserved":"2026-07-19T15:36:31.796Z","dateUpdated":"2026-08-17T04:57:33.289Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-27 21:17:08","lastModifiedDate":"2026-08-17 05:18:01","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:L/UI:N/S:C/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2,"impactScore":6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64555","Ordinal":"1","Title":"KVM: arm64: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops()","CVE":"CVE-2026-64555","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64555","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops()\n\nkvm_hyp_handle_mops() resets the single-step state machine as part of\nrewinding state for a MOPS exception by modifying vcpu_cpsr() and\nwriting the result directly into hardware.\n\nIn the case of nested virtualization, vcpu_cpsr() is a synthetic value\nsuch that the rest of KVM can deal with vEL2 cleanly. That means the\nvalue requires translation before being written into hardware, which is\nunfortunately missing from the MOPS handler.\n\nFix it by directly modifying SPSR_EL2 and avoiding the synthetic state\naltogether, which will be resynchronized on the next 'full' exit back\nto KVM.","Type":"Description","Title":"KVM: arm64: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops()"}]}}}