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CVSS: 7.8EPSS: 0%CPEs: 5EXPL: 0

20 Jul 2020 — An issue was discovered in the Linux kernel 5.5 through 5.7.9, as used in Xen through 4.13.x for x86 PV guests. An attacker may be granted the I/O port permissions of an unrelated task. This occurs because tss_invalidate_io_bitmap mishandling causes a loss of synchronization between the I/O bitmaps of TSS and Xen, aka CID-cadfad870154. Se detectó un problema en el kernel de Linux versiones 5.5 hasta 5.7.9, como es usado en Xen versiones hasta 4.13.x para invitados PV x86. Un atacante puede otorgar los permi... • http://www.openwall.com/lists/oss-security/2020/07/21/2 • CWE-276: Incorrect Default Permissions •

CVSS: 7.8EPSS: 0%CPEs: 6EXPL: 0

07 Jul 2020 — An issue was discovered in Xen through 4.13.x, allowing Intel guest OS users to gain privileges or cause a denial of service because of non-atomic modification of a live EPT PTE. When mapping guest EPT (nested paging) tables, Xen would in some circumstances use a series of non-atomic bitfield writes. Depending on the compiler version and optimisation flags, Xen might expose a dangerous partially written PTE to the hardware, which an attacker might be able to race to exploit. A guest administrator or perhaps... • http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00024.html • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') •

CVSS: 6.5EPSS: 0%CPEs: 4EXPL: 0

07 Jul 2020 — An issue was discovered in Xen through 4.13.x, allowing Arm guest OS users to cause a hypervisor crash because of a missing alignment check in VCPUOP_register_vcpu_info. The hypercall VCPUOP_register_vcpu_info is used by a guest to register a shared region with the hypervisor. The region will be mapped into Xen address space so it can be directly accessed. On Arm, the region is accessed with instructions that require a specific alignment. Unfortunately, there is no check that the address provided by the gue... • http://www.openwall.com/lists/oss-security/2020/07/07/5 • CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer •

CVSS: 8.8EPSS: 0%CPEs: 6EXPL: 0

07 Jul 2020 — An issue was discovered in Xen through 4.13.x, allowing x86 Intel HVM guest OS users to cause a host OS denial of service or possibly gain privileges because of insufficient cache write-back under VT-d. When page tables are shared between IOMMU and CPU, changes to them require flushing of both TLBs. Furthermore, IOMMUs may be non-coherent, and hence prior to flushing IOMMU TLBs, a CPU cache also needs writing back to memory after changes were made. Such writing back of cached data was missing in particular ... • http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00024.html • CWE-400: Uncontrolled Resource Consumption •

CVSS: 6.5EPSS: 0%CPEs: 5EXPL: 0

07 Jul 2020 — An issue was discovered in Xen through 4.13.x, allowing x86 HVM guest OS users to cause a hypervisor crash. An inverted conditional in x86 HVM guests' dirty video RAM tracking code allows such guests to make Xen de-reference a pointer guaranteed to point at unmapped space. A malicious or buggy HVM guest may cause the hypervisor to crash, resulting in Denial of Service (DoS) affecting the entire host. Xen versions from 4.8 onwards are affected. Xen versions 4.7 and earlier are not affected. • http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00024.html • CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer •

CVSS: 6.5EPSS: 0%CPEs: 2EXPL: 0

07 Jul 2020 — An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a host OS crash because of incorrect error handling in event-channel port allocation. The allocation of an event-channel port may fail for multiple reasons: (1) port is already in use, (2) the memory allocation failed, or (3) the port we try to allocate is higher than what is supported by the ABI (e.g., 2L or FIFO) used by the guest or the limit set by an administrator (max_event_channels in xl cfg). Due to the missing error che... • http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00024.html • CWE-754: Improper Check for Unusual or Exceptional Conditions •

CVSS: 5.5EPSS: 0%CPEs: 4EXPL: 2

14 Apr 2020 — An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service because of a bad error path in GNTTABOP_map_grant. Grant table operations are expected to return 0 for success, and a negative number for errors. Some misplaced brackets cause one error path to return 1 instead of a negative value. The grant table code in Linux treats this condition as success, and proceeds with incorrectly initialised state. A buggy or malicious guest can construct its grant table in such a ... • http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00006.html • CWE-755: Improper Handling of Exceptional Conditions •

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

14 Apr 2020 — An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service because of bad continuation handling in GNTTABOP_copy. Grant table operations are expected to return 0 for success, and a negative number for errors. The fix for CVE-2017-12135 introduced a path through grant copy handling where success may be returned to the caller without any action taken. In particular, the status fields of individual operations are left uninitialised, and may result in errant behaviour in... • http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00006.html •

CVSS: 8.8EPSS: 0%CPEs: 8EXPL: 0

14 Apr 2020 — An issue was discovered in xenoprof in Xen through 4.13.x, allowing guest OS users (with active profiling) to obtain sensitive information about other guests, cause a denial of service, or possibly gain privileges. For guests for which "active" profiling was enabled by the administrator, the xenoprof code uses the standard Xen shared ring structure. Unfortunately, this code did not treat the guest as a potential adversary: it trusts the guest not to modify buffer size information or modify head / tail point... • http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00006.html • CWE-909: Missing Initialization of Resource •

CVSS: 5.5EPSS: 0%CPEs: 8EXPL: 0

14 Apr 2020 — An issue was discovered in xenoprof in Xen through 4.13.x, allowing guest OS users (without active profiling) to obtain sensitive information about other guests. Unprivileged guests can request to map xenoprof buffers, even if profiling has not been enabled for those guests. These buffers were not scrubbed. Se detectó un problema en xenoprof en Xen versiones hasta 4.13.x, permitiendo a usuarios invitados del Sistema Operativo (sin perfiles activos) obtener información confidencial sobre otros invitados. Los... • http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00006.html • CWE-212: Improper Removal of Sensitive Information Before Storage or Transfer •