CVE-2020-25603 Detail

Current Description

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.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  7.8 HIGH
Vector:  CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have published a CVSS score for this CVE based on publicly available information at the time of analysis. The CNA has not provided a score within the CVE List.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00008.html Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4JRXMKEMQRQYWYEPHVBIWUEAVQ3LU4FN/ Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DA633Y3G5KX7MKRN4PFEGM3IVTJMBEOM/ Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RJZERRBJN6E6STDCHT4JHP4MI6TKBCJE/
https://www.debian.org/security/2020/dsa-4769 Third Party Advisory 
https://xenbits.xen.org/xsa/advisory-340.html Patch  Vendor Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-401 Missing Release of Memory after Effective Lifetime cwe source acceptance level NIST  

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Change History

7 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2020-25603
NVD Published Date:
09/23/2020
NVD Last Modified:
10/07/2020
Source:
MITRE