CVSS: 7.8EPSS: 0%CPEs: 8EXPL: 0CVE-2020-11739
https://notcve.org/view.php?id=CVE-2020-11739
An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service or possibly gain privileges because of missing memory barriers in read-write unlock paths. The read-write unlock paths don't contain a memory barrier. On Arm, this means a processor is allowed to re-order the memory access with the preceding ones. In other words, the unlock may be seen by another processor before all the memory accesses within the "critical" section. As a consequence, it may be possible to have a writer executing a critical section at the same time as readers or another writer. • http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00006.html http://www.openwall.com/lists/oss-security/2020/04/14/2 http://xenbits.xen.org/xsa/advisory-314.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5M2XRNCHOGGTJQBZQJ7DCV6ZNAKN3LE2 https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NVTP4OYHCTRU3ONFJOFJQVNDFB25KLLG https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YMAW7D2MP • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') •
CVSS: 7.2EPSS: 0%CPEs: 2EXPL: 0CVE-2019-19577
https://notcve.org/view.php?id=CVE-2019-19577
An issue was discovered in Xen through 4.12.x allowing x86 AMD HVM guest OS users to cause a denial of service or possibly gain privileges by triggering data-structure access during pagetable-height updates. When running on AMD systems with an IOMMU, Xen attempted to dynamically adapt the number of levels of pagetables (the pagetable height) in the IOMMU according to the guest's address space size. The code to select and update the height had several bugs. Notably, the update was done without taking a lock which is necessary for safe operation. A malicious guest administrator can cause Xen to access data structures while they are being modified, causing Xen to crash. • http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00011.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/34HBFTYNMQMWIO2GGK7DB6KV4M6R5YPV https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/D5R73AYE53QA32KTMHUVKCX6E52CIS43 https://seclists.org/bugtraq/2020/Jan/21 https://security.gentoo.org/glsa/202003-56 https://www.debian.org/security/2020/dsa-4602 https://xenbits.xen.org/xsa/advisory-311.html • CWE-401: Missing Release of Memory after Effective Lifetime CWE-662: Improper Synchronization •
CVSS: 8.8EPSS: 0%CPEs: 2EXPL: 0CVE-2019-19578
https://notcve.org/view.php?id=CVE-2019-19578
An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to cause a denial of service via degenerate chains of linear pagetables, because of an incorrect fix for CVE-2017-15595. "Linear pagetables" is a technique which involves either pointing a pagetable at itself, or to another pagetable of the same or higher level. Xen has limited support for linear pagetables: A page may either point to itself, or point to another pagetable of the same level (i.e., L2 to L2, L3 to L3, and so on). XSA-240 introduced an additional restriction that limited the "depth" of such chains by allowing pages to either *point to* other pages of the same level, or *be pointed to* by other pages of the same level, but not both. To implement this, we keep track of the number of outstanding times a page points to or is pointed to another page table, to prevent both from happening at the same time. • http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00011.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/34HBFTYNMQMWIO2GGK7DB6KV4M6R5YPV https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/D5R73AYE53QA32KTMHUVKCX6E52CIS43 https://seclists.org/bugtraq/2020/Jan/21 https://security.gentoo.org/glsa/202003-56 https://www.debian.org/security/2020/dsa-4602 https://xenbits.xen.org/xsa/advisory-309.html • CWE-682: Incorrect Calculation •
CVSS: 6.6EPSS: 0%CPEs: 2EXPL: 0CVE-2019-19580
https://notcve.org/view.php?id=CVE-2019-19580
An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to gain host OS privileges by leveraging race conditions in pagetable promotion and demotion operations, because of an incomplete fix for CVE-2019-18421. XSA-299 addressed several critical issues in restartable PV type change operations. Despite extensive testing and auditing, some corner cases were missed. A malicious PV guest administrator may be able to escalate their privilege to that of the host. All security-supported versions of Xen are vulnerable. • http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00011.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/34HBFTYNMQMWIO2GGK7DB6KV4M6R5YPV https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/D5R73AYE53QA32KTMHUVKCX6E52CIS43 https://seclists.org/bugtraq/2020/Jan/21 https://security.gentoo.org/glsa/202003-56 https://www.debian.org/security/2020/dsa-4602 https://xenbits.xen.org/xsa/advisory-310.html • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') •
CVSS: 7.2EPSS: 0%CPEs: 2EXPL: 0CVE-2019-19579
https://notcve.org/view.php?id=CVE-2019-19579
An issue was discovered in Xen through 4.12.x allowing attackers to gain host OS privileges via DMA in a situation where an untrusted domain has access to a physical device (and assignable-add is not used), because of an incomplete fix for CVE-2019-18424. XSA-302 relies on the use of libxl's "assignable-add" feature to prepare devices to be assigned to untrusted guests. Unfortunately, this is not considered a strictly required step for device assignment. The PCI passthrough documentation on the wiki describes alternate ways of preparing devices for assignment, and libvirt uses its own ways as well. Hosts where these "alternate" methods are used will still leave the system in a vulnerable state after the device comes back from a guest. • http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00011.html http://www.openwall.com/lists/oss-security/2019/12/05/7 http://xenbits.xen.org/xsa/advisory-306.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RJYT5FNGM7JSVHHW6B22TSAATBOAPFPD https://seclists.org/bugtraq/2020/Jan/21 https://www.debian.org/security/2020/dsa-4602 https://www.openwall.com/lists/oss-security/2019/11/26/2 https://xenbits.xen.org/xsa/advisory-30 • CWE-20: Improper Input Validation •