When passing through PCI devices, the detach logic in libxl won't remove access permissions to any 64bit memory BARs the device might have. As a result a domain can still have access any 64bit memory BAR when such device is no longer assigned to the domain. For PV domains the permission leak allows the domain itself to map the memory in the page-tables. For HVM it would require a compromised device model or stubdomain to map the leaked memory into the HVM domain p2m.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://xenbits.xenproject.org/xsa/advisory-476.html Patch, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2025/10/24/1 Mailing List, Patch, Third Party Advisory
- http://xenbits.xen.org/xsa/advisory-476.html Patch, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 7.5 · xenNVD modified 2026-10-19 13:10
Affected (CPE criteria) 1
cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*
References 3
- https://xenbits.xenproject.org/xsa/advisory-476.html Patch, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2025/10/24/1 Mailing List, Patch, Third Party Advisory
- http://xenbits.xen.org/xsa/advisory-476.html Patch, Vendor Advisory