CVE-2021-28709

Description

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.)

Category

7.8
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.09%
Vendor Advisory fedoraproject.org Vendor Advisory debian.org Vendor Advisory fedoraproject.org Vendor Advisory gentoo.org Vendor Advisory xenproject.org
Affected: Xen xen
Affected: Xen xen
Affected: Xen xen
Affected: Xen xen
Affected: Xen xen
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-28709?
CVE-2021-28709 has been scored as a high severity vulnerability.
How to fix CVE-2021-28709?
To fix CVE-2021-28709, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-28709 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-28709 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-28709?
CVE-2021-28709 affects Xen xen, Xen xen, Xen xen, Xen xen, Xen xen.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.