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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: 5.6EPSS: 0%CPEs: 5EXPL: 0

lock order inversion in transitive grant copy handling As part of XSA-226 a missing cleanup call was inserted on an error handling path. While doing so, locking requirements were not paid attention to. As a result two cooperating guests granting each other transitive grants can cause locks to be acquired nested within one another, but in respectively opposite order. With suitable timing between the involved grant copy operations this may result in the locking up of a CPU. Inversión del orden de bloqueo en el manejo de la copia de concesión transitiva Como parte de XSA-226 fue insertada una llamada de limpieza que faltaba en una ruta de manejo de errores. • http://www.openwall.com/lists/oss-security/2022/10/11/2 http://xenbits.xen.org/xsa/advisory-411.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TJOMUNGW6VTK5CZZRLWLVVEOUPEQBRHI https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XWSC77GS5NATI3TT7FMVPULUPXR635XQ https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YZVXG7OOOXCX6VIPEMLFDPIPUTFAYWPE https://security.gentoo.org/glsa/202402-07 https:// • CWE-755: Improper Handling of Exceptional Conditions •

CVSS: 5.6EPSS: 0%CPEs: 6EXPL: 0

Racy interactions between dirty vram tracking and paging log dirty hypercalls Activation of log dirty mode done by XEN_DMOP_track_dirty_vram (was named HVMOP_track_dirty_vram before Xen 4.9) is racy with ongoing log dirty hypercalls. A suitably timed call to XEN_DMOP_track_dirty_vram can enable log dirty while another CPU is still in the process of tearing down the structures related to a previously enabled log dirty mode (XEN_DOMCTL_SHADOW_OP_OFF). This is due to lack of mutually exclusive locking between both operations and can lead to entries being added in already freed slots, resulting in a memory leak. Una activación del modo de registro sucio realizada por XEN_DMOP_track_dirty_vram (es llamada HVMOP_track_dirty_vram antes de Xen versión 4.9) es producido con las hiperllamadas de registro sucio en curso. Una llamada a XEN_DMOP_track_dirty_vram con el tiempo apropiado puede habilitar log dirty mientras otra CPU está todavía en el proceso de desmontar las estructuras relacionadas con un modo log dirty previamente habilitado (XEN_DOMCTL_SHADOW_OP_OFF). • http://www.openwall.com/lists/oss-security/2022/04/05/1 http://xenbits.xen.org/xsa/advisory-397.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6ETPM2OVZZ6KOS2L7QO7SIW6XWT5OW3F https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UHFSRVLM2JUCPDC2KGB7ETPQYJLCGBLD https://security.gentoo.org/glsa/202402-07 https://www.debian.org/security/2022/dsa-5117 https://xenbits.xenproject.org/xsa/advisory-397.txt • CWE-667: Improper Locking •

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 •