{"id":"CVE-2026-79603","state":"PUBLISHED","title":"Unconditionally do TLB flushing ahead of page scrubbing","description":"x86 PV guests can free memory pages while still keeping a stale TLB entry\npointing to them.  A TLB flush is only issued by Xen (if needed) when the\npage is re-used.  Since it's possible for the page to be scrubbed ahead of\nthe TLB flush, there's a window where a PV guest can modify an already\nscrubbed page.","publishedAt":"2026-09-08T12:11:21.789Z","updatedAt":"2026-09-08T17:08:33.807Z","severity":{"score":4.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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-511","status":"unknown"}]}],"references":["https://xenbits.xenproject.org/xsa/advisory-511.html","http://xenbits.xen.org/xsa/advisory-511.html","http://www.openwall.com/lists/oss-security/2026/09/08/8"],"weaknesses":["CWE-664"],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/79xxx/CVE-2026-79603.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-79603","state":"PUBLISHED","datePublished":"2026-09-08T12:11:21.789Z","dateUpdated":"2026-09-08T17:08:33.807Z","assignerShortName":"XEN","assignerOrgId":"23aa2041-22e1-471f-9209-9b7396fa234f","dateReserved":"2026-08-25T07:35:05.289Z"},"containers":{"cna":{"title":"Unconditionally do TLB flushing ahead of page scrubbing","descriptions":[{"lang":"en","value":"x86 PV guests can free memory pages while still keeping a stale TLB entry\npointing to them.  A TLB flush is only issued by Xen (if needed) when the\npage is re-used.  Since it's possible for the page to be scrubbed ahead of\nthe TLB flush, there's a window where a PV guest can modify an already\nscrubbed page."}],"affected":[{"vendor":"Xen","product":"Xen","defaultStatus":"unknown","versions":[{"version":"consult Xen advisory XSA-511","status":"unknown"}]}],"references":[{"url":"https://xenbits.xenproject.org/xsa/advisory-511.html"}],"providerMetadata":{"shortName":"XEN","orgId":"23aa2041-22e1-471f-9209-9b7396fa234f","dateUpdated":"2026-09-08T12:11:21.789Z"},"datePublic":"2026-09-08T12:00:00.000Z","impacts":[{"descriptions":[{"lang":"en","value":"Deployments using `xsm=silo scrub-domheap` with the aim of not allowing the\nexchange of information amongst guests are not effective in the presence of\nPV guests."}]}],"configurations":[{"lang":"en","value":"All Xen versions from 4.13 onwards are vulnerable.  Xen versions 4.12 and\nearlier are not vulnerable as they lack the `scrub-domheap` command line\noption.\n\nOnly x86 PV guests can exploit the vulnerability."}],"workarounds":[{"lang":"en","value":"There is no known mitigation."}],"credits":[{"lang":"en","type":"finder","value":"This issue was discovered by Roger Pau Monné of AMD."}]},"adp":[{"title":"CVE Program Container","references":[{"url":"http://xenbits.xen.org/xsa/advisory-511.html"},{"url":"http://www.openwall.com/lists/oss-security/2026/09/08/8"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-09-08T17:08:33.807Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":4.3,"attackVector":"NETWORK","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"LOW","confidentialityImpact":"LOW"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-09-08T13:42:37.092287Z","id":"CVE-2026-79603","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-664","type":"CWE","lang":"en","description":"CWE-664 Improper Control of a Resource Through its Lifetime"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-08T13:42:41.424Z"}}]}}}