high
7.8
CWE
755
Advisory Published
Updated

CVE-2021-28709

First published: Wed Nov 24 2021(Updated: )

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.)

Credit: security@xen.org security@xen.org

Affected SoftwareAffected VersionHow to fix
debian/xen<=4.11.4+107-gef32c7afa2-1
4.14.6-1
4.14.5+94-ge49571868d-1
4.17.1+2-gb773c48e36-1
4.17.2+55-g0b56bed864-1
Xen XAPI>=3.4.0<=4.12.4
Xen XAPI>=4.13.0<=4.13.4
Xen XAPI>=4.14.0<=4.14.3
Xen XAPI=4.15.0
Xen XAPI=4.15.1
Fedora=34
Fedora=35
Debian=11.0

Remedy

https://xenbits.xenproject.org/xsa/advisory-389.txt

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2021-28709?

    CVE-2021-28709 is classified as a medium severity vulnerability affecting certain versions of Xen.

  • How do I fix CVE-2021-28709?

    To fix CVE-2021-28709, update your Xen package to a version that is not affected by this vulnerability.

  • Which software versions are affected by CVE-2021-28709?

    CVE-2021-28709 affects multiple versions of Xen, including but not limited to versions between 4.11.4 and 4.14.3.

  • What impact does CVE-2021-28709 have on system security?

    CVE-2021-28709 can lead to potential exploitation through partially successful P2M updates, posing risks to the stability of x86 HVM and PVH guests.

  • Are there any known workarounds for CVE-2021-28709?

    Currently, the recommended approach is to update to a patched version, as there are no reported workarounds for CVE-2021-28709.

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