{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-63937", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.022Z", "datePublished": "2026-07-19T14:55:34.554Z", "dateUpdated": "2026-07-20T13:41:39.071Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-07-20T13:41:39.071Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer\n\nUse READ_ONCE() when reading entries/indices from the guest-accessible\nPage State Change buffer to defend against TOCTOU bugs.\n\nDon't bother with READ_ONCE()/WRITE_ONCE() for cases where KVM is writing\n(and not consuming the result!), as the guest isn't supposed to touch the\nbuffer while it's being processed. I.e. using READ_ONCE() is all about\nprotecting against misbehaving guests."}], "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"}}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["arch/x86/kvm/svm/sev.c"], "versions": [{"version": "9b54e248d2644be71cb394eb85f31ad99e023a05", "lessThan": "bd232801ef1d1fd985d2d4ca3cd1d888303ca86f", "status": "affected", "versionType": "git"}, {"version": "9b54e248d2644be71cb394eb85f31ad99e023a05", "lessThan": "b1dfaa6f7a957726a6800135be3659fbe4bbf2a4", "status": "affected", "versionType": "git"}, {"version": "9b54e248d2644be71cb394eb85f31ad99e023a05", "lessThan": "edbbe88f83b524434974e84808d3093199d67c24", "status": "affected", "versionType": "git"}, {"version": "9b54e248d2644be71cb394eb85f31ad99e023a05", "lessThan": "c8cc238093ca6c99267032f6cfe78f59389f3157", "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/x86/kvm/svm/sev.c"], "versions": [{"version": "6.11", "status": "affected"}, {"version": "0", "lessThan": "6.11", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.93", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.35", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.12", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1", "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": "6.11", "versionEndExcluding": "6.12.93"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.18.35"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.0.12"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/bd232801ef1d1fd985d2d4ca3cd1d888303ca86f"}, {"url": "https://git.kernel.org/stable/c/b1dfaa6f7a957726a6800135be3659fbe4bbf2a4"}, {"url": "https://git.kernel.org/stable/c/edbbe88f83b524434974e84808d3093199d67c24"}, {"url": "https://git.kernel.org/stable/c/c8cc238093ca6c99267032f6cfe78f59389f3157"}], "title": "KVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{}

{"bugzilla": {"description": "kernel: KVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer", "id": "2502399", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2502399"}, "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-367", "details": ["A flaw was found in the Linux kernel's Kernel-based Virtual Machine (KVM) with Secure Encrypted Virtualization (SEV). This time-of-check to time-of-use (TOCTOU) vulnerability exists when KVM processes the guest-accessible Page State Change (PSC) buffer. A misbehaving guest could exploit this timing issue by modifying the buffer after it has been checked but before it is used, potentially leading to an impact on the integrity of the virtualized environment."], "name": "CVE-2026-63937", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "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": "Fix deferred", "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": "2026-07-19T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-63937\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-63937\nhttps://lore.kernel.org/linux-cve-announce/2026071951-CVE-2026-63937-80da@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9b54e248d2644be71cb394eb85f31ad99e023a05,bd232801ef1d1fd985d2d4ca3cd1d888303ca86f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9b54e248d2644be71cb394eb85f31ad99e023a05,b1dfaa6f7a957726a6800135be3659fbe4bbf2a4)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9b54e248d2644be71cb394eb85f31ad99e023a05,edbbe88f83b524434974e84808d3093199d67c24)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9b54e248d2644be71cb394eb85f31ad99e023a05,c8cc238093ca6c99267032f6cfe78f59389f3157)"}}], "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": "semver", "value": "6.11"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.11)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.93,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.35,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.0.12,7.1.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1,*]"}}], "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": "2026-07-22T04:00:04.778683+00:00", "updated": "2026-07-22T18:30:03.534536+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-367", "CWE-362"]}