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. Privilege escalation is thought to be very difficult but cannot be ruled out. Additionally, there is a potential memory leak of 4kb per guest boot, under memory pressure. Only Xen on AMD CPUs is vulnerable. Xen running on Intel CPUs is not vulnerable. ARM systems are not vulnerable. Only systems where guests are given direct access to physical devices are vulnerable. Systems which do not use PCI pass-through are not vulnerable. Only HVM guests can exploit the vulnerability. PV and PVH guests cannot. All versions of Xen with IOMMU support are vulnerable.
Published 2019-12-11 18:16:19
Updated 2020-08-24 17:37:01
Source MITRE
View at NVD,   CVE.org
Vulnerability category: Gain privilegeDenial of service

Exploit prediction scoring system (EPSS) score for CVE-2019-19577

0.05%
Probability of exploitation activity in the next 30 days EPSS Score History
~ 13 %
Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2019-19577

Base Score Base Severity CVSS Vector Exploitability Score Impact Score Score Source First Seen
7.2
HIGH AV:L/AC:L/Au:N/C:C/I:C/A:C
3.9
10.0
NIST
7.2
HIGH CVSS:3.1/AV:P/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
0.5
6.0
NIST

CWE ids for CVE-2019-19577

  • The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.
    Assigned by: nvd@nist.gov (Primary)
  • The product utilizes multiple threads or processes to allow temporary access to a shared resource that can only be exclusive to one process at a time, but it does not properly synchronize these actions, which might cause simultaneous accesses of this resource by multiple threads or processes.
    Assigned by: nvd@nist.gov (Primary)

References for CVE-2019-19577

Products affected by CVE-2019-19577

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