An issue was discovered in Xen through 4.14.x. There are missing memory barriers when accessing/allocating an event channel. Event channels control structures can be accessed lockless as long as the port is considered to be valid. Such a sequence is missing an appropriate memory barrier (e.g., smp_*mb()) to prevent both the compiler and CPU from re-ordering access. A malicious guest may be able to cause a hypervisor crash resulting in a Denial of Service (DoS). Information leak and privilege escalation cannot be excluded. Systems running all versions of Xen are affected. Whether a system is vulnerable will depend on the CPU and compiler used to build Xen. For all systems, the presence and the scope of the vulnerability depend on the precise re-ordering performed by the compiler used to build Xen. We have not been able to survey compilers; consequently we cannot say which compiler(s) might produce vulnerable code (with which code generation options). GCC documentation clearly suggests that re-ordering is possible. Arm systems will also be vulnerable if the CPU is able to re-order memory access. Please consult your CPU vendor. x86 systems are only vulnerable if a compiler performs re-ordering.
Published 2020-09-23 22:15:14
Updated 2022-04-28 18:19:45
Source MITRE
View at NVD,   CVE.org
Vulnerability category: Gain privilegeDenial of service

Exploit prediction scoring system (EPSS) score for CVE-2020-25603

0.05%
Probability of exploitation activity in the next 30 days EPSS Score History
~ 12 %
Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2020-25603

Base Score Base Severity CVSS Vector Exploitability Score Impact Score Score Source First Seen
4.6
MEDIUM AV:L/AC:L/Au:N/C:P/I:P/A:P
3.9
6.4
NIST
7.8
HIGH CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
1.8
5.9
NIST

CWE ids for CVE-2020-25603

  • The code contains a control flow path that does not reflect the algorithm that the path is intended to implement, leading to incorrect behavior any time this path is navigated.
    Assigned by: nvd@nist.gov (Primary)

References for CVE-2020-25603

Products affected by CVE-2020-25603

This web site uses cookies for managing your session, storing preferences, website analytics and additional purposes described in our privacy policy.
By using this web site you are agreeing to CVEdetails.com terms of use!