6.9
CVSSv2

CVE-2021-28705

Published: 24/11/2021 Updated: 04/02/2024
CVSS v2 Base Score: 6.9 | Impact Score: 10 | Exploitability Score: 3.4
CVSS v3 Base Score: 7.8 | Impact Score: 5.9 | Exploitability Score: 1.8
VMScore: 614
Vector: AV:L/AC:M/Au:N/C:C/I:C/A:C

Vulnerability Summary

issues with partially successful P2M updates on x86 T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] x86 HVM and PVH guests may be started in populate-on-demand (PoD) mode, to provide a way for them to later easily have more memory assigned. Guests are permitted to control certain P2M aspects of individual pages via hypercalls. These hypercalls may act on ranges of pages specified via page orders (resulting in a power-of-2 number of pages). In some cases the hypervisor carries out the requests by splitting them into smaller chunks. Error handling in certain PoD cases has been insufficient in that in particular partial success of some operations was not properly accounted for. There are two code paths affected - page removal (CVE-2021-28705) and insertion of new pages (CVE-2021-28709). (We provide one patch which combines the fix to both issues.)

Vulnerability Trend

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xen xen 4.15.0

xen xen 4.15.1

xen xen

fedoraproject fedora 34

fedoraproject fedora 35

debian debian linux 11.0

Vendor Advisories

Multiple vulnerabilities have been discovered in the Xen hypervisor, which could result in privilege escalation, denial of service or information leaks For the stable distribution (bullseye), these problems have been fixed in version 4143+32-g9de3671772-1~deb11u1 We recommend that you upgrade your xen packages For the detailed security status ...
Several security issues have been identified in Citrix Hypervisor, that may each allow privileged code in a guest VM to cause the host to crash or become unresponsive  ...