CVE-2020-11739
Published Apr 14, 2020
Last updated a year ago
Overview
- Description
- 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. In other words, many of the assumptions (e.g., a variable cannot be modified after a check) in the critical sections are not safe anymore. The read-write locks are used in hypercalls (such as grant-table ones), so a malicious guest could exploit the race. For instance, there is a small window where Xen can leak memory if XENMAPSPACE_grant_table is used concurrently. A malicious guest may be able to leak memory, or cause a hypervisor crash resulting in a Denial of Service (DoS). Information leak and privilege escalation cannot be excluded.
- Source
- cve@mitre.org
- NVD status
- Modified
Social media
- Hype score
- Not currently trending
Risk scores
CVSS 3.1
- Type
- Primary
- Base score
- 7.8
- Impact score
- 6
- Exploitability score
- 1.1
- Vector string
- CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
- Severity
- HIGH
CVSS 2.0
- Type
- Primary
- Base score
- 6.9
- Impact score
- 10
- Exploitability score
- 3.4
- Vector string
- AV:L/AC:M/Au:N/C:C/I:C/A:C
Weaknesses
- nvd@nist.gov
- CWE-362
Configurations
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