{"id":"CVE-2026-42492","state":"PUBLISHED","title":"vIRQ event channel binding may break Xenstore","description":"Xenstore, to have an up-to-date picture of the entire system, wants to\nknow of domains appearing and disappearing.  To make this more robust, a\nnew XEN_DOMCTL_get_domain_state was introduced.  The management of the\nbitmap underlying that operation is tied into the binding of the\nVIRQ_DOM_EXC virtual IRQ.  Unfortunately an error path there would tear\ndown the bitmap even in cases when it wasn't set up.  Unprivileged domains\ncan trigger that error path.","publishedAt":"2026-07-28T12:31:28.304Z","updatedAt":"2026-07-28T16:33:22.683Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"CISA-ADP"},"assigner":"XEN","products":["Xen Xen"],"affected":[{"vendor":"Xen","product":"Xen","defaultStatus":"unknown","versions":[{"version":"consult Xen advisory XSA-496","status":"unknown"}]}],"references":["https://xenbits.xenproject.org/xsa/advisory-496.html","http://xenbits.xen.org/xsa/advisory-496.html","http://www.openwall.com/lists/oss-security/2026/07/28/13"],"weaknesses":["CWE-459"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/42xxx/CVE-2026-42492.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-42492","state":"PUBLISHED","datePublished":"2026-07-28T12:31:28.304Z","dateUpdated":"2026-07-28T16:33:22.683Z","assignerShortName":"XEN","assignerOrgId":"23aa2041-22e1-471f-9209-9b7396fa234f","dateReserved":"2026-04-27T14:20:24.139Z"},"containers":{"cna":{"title":"vIRQ event channel binding may break Xenstore","descriptions":[{"lang":"en","value":"Xenstore, to have an up-to-date picture of the entire system, wants to\nknow of domains appearing and disappearing.  To make this more robust, a\nnew XEN_DOMCTL_get_domain_state was introduced.  The management of the\nbitmap underlying that operation is tied into the binding of the\nVIRQ_DOM_EXC virtual IRQ.  Unfortunately an error path there would tear\ndown the bitmap even in cases when it wasn't set up.  Unprivileged domains\ncan trigger that error path."}],"affected":[{"vendor":"Xen","product":"Xen","defaultStatus":"unknown","versions":[{"version":"consult Xen advisory XSA-496","status":"unknown"}]}],"references":[{"url":"https://xenbits.xenproject.org/xsa/advisory-496.html"}],"providerMetadata":{"shortName":"XEN","orgId":"23aa2041-22e1-471f-9209-9b7396fa234f","dateUpdated":"2026-07-28T12:31:28.304Z"},"datePublic":"2026-07-28T12:00:00.000Z","impacts":[{"descriptions":[{"lang":"en","value":"An unprivileged domain can affect the operation of Xenstore, potentially\nleading to a Denial of Service (DoS) affecting the entire host.  A\nhypervisor crash with similar host wide effect also is possible, albeit\nunlikely."}]}],"configurations":[{"lang":"en","value":"Xen 4.21 and onwards are vulnerable.  Xen 4.20 and older are not\nvulnerable."}],"workarounds":[{"lang":"en","value":"There is no known mitigation."}],"credits":[{"lang":"en","type":"finder","value":"This issue was discovered by Grygorii Strashko of EPAM."}]},"adp":[{"title":"CVE Program Container","references":[{"url":"http://xenbits.xen.org/xsa/advisory-496.html"},{"url":"http://www.openwall.com/lists/oss-security/2026/07/28/13"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-07-28T16:33:22.683Z"}},{"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:N/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-07-28T15:56:49.876014Z","id":"CVE-2026-42492","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-459","type":"CWE","lang":"en","description":"CWE-459 Incomplete Cleanup"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-28T15:56:54.437Z"}}]}}}