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CVSS: 7.8EPSS: 0%CPEs: 4EXPL: 0

x86 shadow plus log-dirty mode use-after-free In environments where host assisted address translation is necessary but Hardware Assisted Paging (HAP) is unavailable, Xen will run guests in so called shadow mode. Shadow mode maintains a pool of memory used for both shadow page tables as well as auxiliary data structures. To migrate or snapshot guests, Xen additionally runs them in so called log-dirty mode. The data structures needed by the log-dirty tracking are part of aformentioned auxiliary data. In order to keep error handling efforts within reasonable bounds, for operations which may require memory allocations shadow mode logic ensures up front that enough memory is available for the worst case requirements. • http://www.openwall.com/lists/oss-security/2023/03/21/1 http://xenbits.xen.org/xsa/advisory-427.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5L6PM4RE7MUE6OWA32ZVOXCP235RM2TM https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/APBMS2Q6746AXAFAITNJMGBNFGNMVLWR https://security.gentoo.org/glsa/202402-07 https://www.debian.org/security/2023/dsa-5378 https://xenbits.xenproject.org/xsa/advisory-427.txt • CWE-416: Use After Free •

CVSS: 5.5EPSS: 0%CPEs: 4EXPL: 0

A PV guest could DoS Xen while unmapping a grant To address XSA-380, reference counting was introduced for grant mappings for the case where a PV guest would have the IOMMU enabled. PV guests can request two forms of mappings. When both are in use for any individual mapping, unmapping of such a mapping can be requested in two steps. The reference count for such a mapping would then mistakenly be decremented twice. Underflow of the counters gets detected, resulting in the triggering of a hypervisor bug check. • http://www.openwall.com/lists/oss-security/2022/01/25/3 https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OMR6UBGJW6JKND7IILGQ2CU35EQPF3E3 https://security.gentoo.org/glsa/202208-23 https://www.debian.org/security/2022/dsa-5117 https://xenbits.xenproject.org/xsa/advisory-394.txt • CWE-191: Integer Underflow (Wrap or Wraparound) •

CVSS: 7.0EPSS: 0%CPEs: 1EXPL: 0

grant table v2 status pages may remain accessible after de-allocation (take two) 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. • https://security.gentoo.org/glsa/202402-07 https://xenbits.xenproject.org/xsa/advisory-387.txt •

CVSS: 8.6EPSS: 0%CPEs: 4EXPL: 0

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 permite tener cerca de 16TiB de memoria, puede ser capaz de emitir hypercalls para aumentar su asignación de memoria más allá del límite establecido por el administrador. Esto es el resultado de un cálculo realizado con precisión de 32 bits, que puede desbordarse. • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I7ZGWVVRI4XY2XSTBI3XEMWBXPDVX6OT https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PXUI4VMD52CH3T7YXAG3J2JW7ZNN3SXF https://security.gentoo.org/glsa/202402-07 https://www.debian.org/security/2021/dsa-5017 https://xenbits.xenproject.org/xsa/advisory-385.txt • CWE-770: Allocation of Resources Without Limits or Throttling •

CVSS: 5.5EPSS: 0%CPEs: 5EXPL: 0

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, starving other domains or causing issues in the hypervisor itself. Note that a domain may map its own grants, i.e. there is no need for multiple domains to be involved here. A pair of "cooperating" guests may, however, cause the effects to be more severe. bucles de larga duración en el manejo de la tabla de concesiones. • http://www.openwall.com/lists/oss-security/2021/09/01/2 https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FZCNPSRPGFCQRYE2BI4D4Q4SCE56ANV2 https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LPRVHW4J4ZCPPOHZEWP5MOJT7XDGFFPJ https://security.gentoo.org/glsa/202208-23 https://www.debian.org/security/2021/dsa-4977 https:/&#x • CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') •