CVE-2026-64555

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-64555", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.796Z", "datePublished": "2026-07-27T20:10:42.259Z", "dateUpdated": "2026-08-17T04:57:33.289Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:57:33.289Z"}, "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": {"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"}, "scenarios": [{"lang": "en", "value": "AV:L - The attacker must be executing code inside a KVM/arm64 guest on the affected host \u2014 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 \u2014 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 \u2014 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."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["arch/arm64/kvm/hyp/include/hyp/switch.h"], "versions": [{"version": "2de451a329cf662beeba71f63c7f83ee24ca6642", "lessThan": "10a568010e827108d149779908850afaec898846", "status": "affected", "versionType": "git"}, {"version": "2de451a329cf662beeba71f63c7f83ee24ca6642", "lessThan": "884b44256041ec6b2dcbe8e6a67384d26145cba1", "status": "affected", "versionType": "git"}, {"version": "2de451a329cf662beeba71f63c7f83ee24ca6642", "lessThan": "dd3b237eb7780d65eae296d3d3a70012b6e7a02f", "status": "affected", "versionType": "git"}, {"version": "2de451a329cf662beeba71f63c7f83ee24ca6642", "lessThan": "ff1022c3de46753eb7eba2f6efd990569e66ff95", "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/hyp/include/hyp/switch.h"], "versions": [{"version": "6.7", "status": "affected"}, {"version": "0", "lessThan": "6.7", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.97", "lessThanOrEqual": "6.12.*", "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": "6.7", "versionEndExcluding": "6.12.97"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.18.40"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "7.2"}]}]}], "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"}}}}

{}

{"affected": [{"affectedData": [{"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"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "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."}], "id": "CVE-2026-64555", "lastModified": "2026-11-03T18:15:39.353", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.0, "impactScore": 6.0, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-07-27T21:17:08.580", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/10a568010e827108d149779908850afaec898846"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/884b44256041ec6b2dcbe8e6a67384d26145cba1"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/dd3b237eb7780d65eae296d3d3a70012b6e7a02f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ff1022c3de46753eb7eba2f6efd990569e66ff95"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Awaiting Analysis"}

{"bugzilla": {"description": "kernel: KVM: arm64: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops()", "id": "2507799", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2507799"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-681", "details": ["A flaw was found in the Linux kernel's Kernel-based Virtual Machine (KVM) for ARM64 architecture, specifically affecting nested virtualization. The kvm_hyp_handle_mops() function, responsible for handling certain virtualization operations, incorrectly restored the SPSR_EL2 register. This occurred because a synthetic value used for nested virtualization was written directly to hardware without proper translation, leading to an improper reset of the single-step state machine. This could potentially impact the stability or security of nested virtualized environments."], "name": "CVE-2026-64555", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-07-27T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-64555\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-64555\nhttps://lore.kernel.org/linux-cve-announce/2026072738-CVE-2026-64555-037b@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[2de451a329cf662beeba71f63c7f83ee24ca6642,10a568010e827108d149779908850afaec898846)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[2de451a329cf662beeba71f63c7f83ee24ca6642,884b44256041ec6b2dcbe8e6a67384d26145cba1)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[2de451a329cf662beeba71f63c7f83ee24ca6642,dd3b237eb7780d65eae296d3d3a70012b6e7a02f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[2de451a329cf662beeba71f63c7f83ee24ca6642,ff1022c3de46753eb7eba2f6efd990569e66ff95)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.7"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.7)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.97,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.40,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.5,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2-rc4,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-07-28T03:45:05.004378+00:00", "updated": "2026-08-05T00:15:04.480802+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}