Description
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.
Affected products
xen: xen
References3
- xenbits.xenproject.org/xsa/advisory-476.html PatchVendor Advisory
- xenbits.xen.org/xsa/advisory-476.html PatchVendor Advisory
- www.openwall.com/lists/oss-security/2025/10/24/1 Mailing ListPatchThird Party Advisory
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - EPSS — exploit probability
- 0% percentile: 38 · as of 10 November 2026
- CWE
- CWE-672
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.