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HIGH · 7.8

CVE-2021-28697

grant table v2 status pages may remain accessible after de-allocation Guest get permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a g...

Vulnerability Description

grant table v2 status pages may remain accessible after de-allocation Guest get permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, get de-allocated when a guest switched (back) from v2 to v1. The freeing of such pages requires that the hypervisor know where in the guest these pages were mapped. The hypervisor tracks only one use within guest space, but racing requests from the guest to insert mappings of these pages may result in any of them to become mapped in multiple locations. Upon switching back from v2 to v1, the guest would then retain access to a page that was freed and perhaps re-used for other purposes.

CVSS Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH

Affected Products

VendorProductVersions
XenXen>= 4.0.0, <= 4.15.0
FedoraprojectFedora33
DebianDebian Linux11.0

Related Weaknesses (CWE)

CWE-362

References

FAQ

What is CVE-2021-28697?

CVE-2021-28697 is a vulnerability with a CVSS score of 7.8 (HIGH). grant table v2 status pages may remain accessible after de-allocation Guest get permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a g...

How severe is CVE-2021-28697?

CVE-2021-28697 has been rated HIGH with a CVSS base score of 7.8/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2021-28697?

Check the references section above for vendor advisories and patch information. Affected products include: Xen Xen, Fedoraproject Fedora, Debian Debian Linux.