{"id":"CVE-2026-62430","state":"PUBLISHED","title":"x86: Out-of-bounds read in vRTC emulation","description":"Accesses to the CMOS memory contents are done using an indirect IO port\npair.  Therefore Xen needs to cache the guest chosen index, and one of\nthe usages of the index didn't take the necessary locking to avoid\nconcurrent changes.  As a result, a guest could change the index after\nit being checked, causing a subsequent out-of-bound read access to the\ncontents of an array.","publishedAt":"2026-07-28T12:32:33.150Z","updatedAt":"2026-07-28T16:33:30.367Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","source":"CISA-ADP"},"assigner":"XEN","products":["Xen Xen"],"affected":[{"vendor":"Xen","product":"Xen","defaultStatus":"unknown","versions":[{"version":"consult Xen advisory XSA-503","status":"unknown"}]}],"references":["https://xenbits.xenproject.org/xsa/advisory-503.html","http://xenbits.xen.org/xsa/advisory-503.html","http://www.openwall.com/lists/oss-security/2026/07/28/19"],"weaknesses":["CWE-362"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/62xxx/CVE-2026-62430.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-62430","state":"PUBLISHED","datePublished":"2026-07-28T12:32:33.150Z","dateUpdated":"2026-07-28T16:33:30.367Z","assignerShortName":"XEN","assignerOrgId":"23aa2041-22e1-471f-9209-9b7396fa234f","dateReserved":"2026-07-14T10:28:12.655Z"},"containers":{"cna":{"title":"x86: Out-of-bounds read in vRTC emulation","descriptions":[{"lang":"en","value":"Accesses to the CMOS memory contents are done using an indirect IO port\npair.  Therefore Xen needs to cache the guest chosen index, and one of\nthe usages of the index didn't take the necessary locking to avoid\nconcurrent changes.  As a result, a guest could change the index after\nit being checked, causing a subsequent out-of-bound read access to the\ncontents of an array."}],"affected":[{"vendor":"Xen","product":"Xen","defaultStatus":"unknown","versions":[{"version":"consult Xen advisory XSA-503","status":"unknown"}]}],"references":[{"url":"https://xenbits.xenproject.org/xsa/advisory-503.html"}],"providerMetadata":{"shortName":"XEN","orgId":"23aa2041-22e1-471f-9209-9b7396fa234f","dateUpdated":"2026-07-28T12:32:33.150Z"},"datePublic":"2026-07-28T12:00:00.000Z","impacts":[{"descriptions":[{"lang":"en","value":"An attacker can read out-of-bounds, this is limited to Xen data, and not\ndata belonging to other guests."}]}],"configurations":[{"lang":"en","value":"All Xen versions from 3.2 onwards are vulnerable.  Xen versions 3.1 and\nearlier are not vulnerable."}],"workarounds":[{"lang":"en","value":"Running only PV or PVH guests will avoid the vulnerability."}]},"adp":[{"title":"CVE Program Container","references":[{"url":"http://xenbits.xen.org/xsa/advisory-503.html"},{"url":"http://www.openwall.com/lists/oss-security/2026/07/28/19"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-07-28T16:33:30.367Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.5,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-07-28T15:50:31.706627Z","id":"CVE-2026-62430","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-362","type":"CWE","lang":"en","description":"CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-28T15:50:36.149Z"}}]}}}