
CVE-2021-28706 – Gentoo Linux Security Advisory 202402-07
https://notcve.org/view.php?id=CVE-2021-28706
24 Nov 2021 — guests may exceed their designated memory limit When a guest is permitted to have close to 16TiB of memory, it may be able to issue hypercalls to increase its memory allocation beyond the administrator established limit. This is a result of a calculation done with 32-bit precision, which may overflow. It would then only be the overflowed (and hence small) number which gets compared against the established upper bound. Los huéspedes pueden exceder su límite de memoria designado Cuando a un huésped se le perm... • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I7ZGWVVRI4XY2XSTBI3XEMWBXPDVX6OT • CWE-770: Allocation of Resources Without Limits or Throttling •

CVE-2021-28707 – Gentoo Linux Security Advisory 202402-07
https://notcve.org/view.php?id=CVE-2021-28707
24 Nov 2021 — PoD operations on misaligned GFNs 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). The i... • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I7ZGWVVRI4XY2XSTBI3XEMWBXPDVX6OT •

CVE-2021-28708 – Gentoo Linux Security Advisory 202402-07
https://notcve.org/view.php?id=CVE-2021-28708
24 Nov 2021 — PoD operations on misaligned GFNs 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). The i... • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I7ZGWVVRI4XY2XSTBI3XEMWBXPDVX6OT •

CVE-2021-28709 – Gentoo Linux Security Advisory 202402-07
https://notcve.org/view.php?id=CVE-2021-28709
24 Nov 2021 — 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 numbe... • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I7ZGWVVRI4XY2XSTBI3XEMWBXPDVX6OT • CWE-755: Improper Handling of Exceptional Conditions •

CVE-2021-28701 – Gentoo Linux Security Advisory 202208-23
https://notcve.org/view.php?id=CVE-2021-28701
08 Sep 2021 — Another race in XENMAPSPACE_grant_table handling Guests are 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, are de-allocated when a guest switches (back) from v2 to v1. Freeing such pages requires that the hypervisor enforce that no parallel request can result in the addition of a mapping of such a page to a guest. That enforcement was missing, allowing guests to retain... • http://www.openwall.com/lists/oss-security/2021/09/08/2 • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') •

CVE-2021-28697 – Gentoo Linux Security Advisory 202208-23
https://notcve.org/view.php?id=CVE-2021-28697
27 Aug 2021 — 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... • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') •

CVE-2021-28698 – Gentoo Linux Security Advisory 202208-23
https://notcve.org/view.php?id=CVE-2021-28698
27 Aug 2021 — long running loops in grant table handling In order to properly monitor resource use, Xen maintains information on the grant mappings a domain may create to map grants offered by other domains. In the process of carrying out certain actions, Xen would iterate over all such entries, including ones which aren't in use anymore and some which may have been created but never used. If the number of entries for a given domain is large enough, this iterating of the entire table may tie up a CPU for too long, starvi... • http://www.openwall.com/lists/oss-security/2021/09/01/2 • CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') •

CVE-2021-28699 – Gentoo Linux Security Advisory 202208-23
https://notcve.org/view.php?id=CVE-2021-28699
27 Aug 2021 — inadequate grant-v2 status frames array bounds check The v2 grant table interface separates grant attributes from grant status. That is, when operating in this mode, a guest has two tables. As a result, guests also need to be able to retrieve the addresses that the new status tracking table can be accessed through. For 32-bit guests on x86, translation of requests has to occur because the interface structure layouts commonly differ between 32- and 64-bit. The translation of the request to obtain the frame n... • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID •

CVE-2021-28692 – Debian Security Advisory 4931-1
https://notcve.org/view.php?id=CVE-2021-28692
28 Jun 2021 — inappropriate x86 IOMMU timeout detection / handling IOMMUs process commands issued to them in parallel with the operation of the CPU(s) issuing such commands. In the current implementation in Xen, asynchronous notification of the completion of such commands is not used. Instead, the issuing CPU spin-waits for the completion of the most recently issued command(s). Some of these waiting loops try to apply a timeout to fail overly-slow commands. The course of action upon a perceived timeout actually being det... • https://security.gentoo.org/glsa/202107-30 • CWE-269: Improper Privilege Management •

CVE-2021-28689
https://notcve.org/view.php?id=CVE-2021-28689
11 Jun 2021 — x86: Speculative vulnerabilities with bare (non-shim) 32-bit PV guests 32-bit x86 PV guest kernels run in ring 1. At the time when Xen was developed, this area of the i386 architecture was rarely used, which is why Xen was able to use it to implement paravirtualisation, Xen's novel approach to virtualization. In AMD64, Xen had to use a different implementation approach, so Xen does not use ring 1 to support 64-bit guests. With the focus now being on 64-bit systems, and the availability of explicit hardware ... • https://xenbits.xenproject.org/xsa/advisory-370.txt • CWE-212: Improper Removal of Sensitive Information Before Storage or Transfer •