CVE-2021-28707

PoD operations on misaligned GFNs This 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 assigne...

CVE-2021-28705

issues with partially successful P2M updates on x86 This 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...

PoD operations on misaligned GFNs

ISSUE DESCRIPTION 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 specifie...

issues with partially successful P2M updates on x86

ISSUE DESCRIPTION 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 specifie...

grant table v2 status pages may remain accessible after de-allocation (take two)

ISSUE DESCRIPTION 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...

Xen 缓冲区错误漏洞

Xen is an open source virtual machine monitor product from the University of Cambridge, UK. The product enables different and incompatible operating systems to run on the same computer and supports migration at runtime to ensure uptime and avoid downtime. A buffer error vulnerability exists in Xe...

Another race in XENMAPSPACE_grant_table handling

ISSUE DESCRIPTION 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...

grant table v2 status pages may remain accessible after de-allocation

ISSUE DESCRIPTION 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...

Xen Paging Tables Race Condition (XSA-328)

According to its self-reported version number, the Xen hypervisor installed on the remote host is affected by an issue 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, X...

Fedora 32 : kernel (2021-8d45d297c6)

The remote Fedora 32 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2021-8d45d297c6 advisory. - An issue was discovered in the Linux kernel 3.11 through 5.10.16, as used by Xen. To service requests to the PV backend, the driver maps grant...

FreeBSD -- Xen grant mapping error handling issues

Problem Description: Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one reported to the backend driver, and the backend driver then loops over the results, performing follow-up actions based on...

CVE-2021-26932

An issue was discovered in the Linux kernel 3.2 through 5.10.16, as used by Xen. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one is reported to the backend driver, and the backend driver then...

Design/Logic Flaw

An issue was discovered in the Linux kernel 3.2 through 5.10.16, as used by Xen. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one is reported to the backend driver, and the backend driver then...

CVE-2021-26932

An issue was discovered in the Linux kernel 3.2 through 5.10.16, as used by Xen. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one is reported to the backend driver, and the backend driver then...

stack corruption from XSA-346 change

ISSUE DESCRIPTION One of the two changes for XSA-346 introduced an on-stack array. The check for guarding against overrunning this array was off by one, allowing for corruption of the first stack slot immediately following this array. IMPACT A malicious or buggy HVM or PVH guest can cause Xen to...

CVE-2020-27672

A race condition flaw was found in the Xen code responsible for handling the updating of the hypervisor's own page tables. This flaw allows a malicious guest to cause a denial of service, host data corruption, or potential privilege escalation. The highest threat from this vulnerability is to...

CVE-2020-27671

CVE-2020-27671 affects Xen 4.14.x and earlier on x86 HVM/PVH guests. The issue arises from mishandling coalescing of per-page IOMMU TLB flushes in the Xen IOMMU path, enabling a guest OS user to cause denial of service (data corruption), data leaks, or potentially a privilege escalation. Connecte...

undue deferral of IOMMU TLB flushes

ISSUE DESCRIPTION To efficiently change the physical to machine address mappings of a larger range of addresses for fully virtualized guests, Xen contains an optimization to coalesce per-page IOMMU TLB flushes into a single, wider flush after all adjustments have been made. While this is fine to ...

x86: Race condition in Xen mapping code

ISSUE DESCRIPTION The Xen code handling the updating of the hypervisor's own pagetables tries to use 2MiB and 1GiB superpages as much as possible to maximize TLB efficiency. Some of the operations for checking and coalescing superpages take non-negligible amount of time; to avoid potential lock...

CVE-2020-25596

A flaw was found in Xen. One of Xen's sanitization paths injects a GP fault and incorrectly delivers it twice to the guest. This flaw allows malicious or buggy user space to crash the guest kernel, resulting in a VM denial of service. Mitigation Running only x86 PVH/HVM guests avoids the...