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Vulnerability Details : CVE-2020-25597

An issue was discovered in Xen through 4.14.x. There is mishandling of the constraint that once-valid event channels may not turn invalid. Logic in the handling of event channel operations in Xen assumes that an event channel, once valid, will not become invalid over the life time of a guest. However, operations like the resetting of all event channels may involve decreasing one of the bounds checked when determining validity. This may lead to bug checks triggering, crashing the host. An unprivileged guest may be able to crash Xen, leading to a Denial of Service (DoS) for the entire system. All Xen versions from 4.4 onwards are vulnerable. Xen versions 4.3 and earlier are not vulnerable. Only systems with untrusted guests permitted to create more than the default number of event channels are vulnerable. This number depends on the architecture and type of guest. For 32-bit x86 PV guests, this is 1023; for 64-bit x86 PV guests, and for all ARM guests, this number is 4095. Systems where untrusted guests are limited to fewer than this number are not vulnerable. Note that xl and libxl limit max_event_channels to 1023 by default, so systems using exclusively xl, libvirt+libxl, or their own toolstack based on libxl, and not explicitly setting max_event_channels, are not vulnerable.
Publish Date : 2020-09-23 Last Update Date : 2020-11-11
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- CVSS Scores & Vulnerability Types

CVSS Score
6.1
Confidentiality Impact Partial (There is considerable informational disclosure.)
Integrity Impact Partial (Modification of some system files or information is possible, but the attacker does not have control over what can be modified, or the scope of what the attacker can affect is limited.)
Availability Impact Complete (There is a total shutdown of the affected resource. The attacker can render the resource completely unavailable.)
Access Complexity Low (Specialized access conditions or extenuating circumstances do not exist. Very little knowledge or skill is required to exploit. )
Authentication Not required (Authentication is not required to exploit the vulnerability.)
Gained Access None
Vulnerability Type(s) Denial Of ServiceOverflow
CWE ID 119

- Products Affected By CVE-2020-25597

# Product Type Vendor Product Version Update Edition Language
1 OS XEN XEN * * * * Version Details Vulnerabilities

- Number Of Affected Versions By Product

Vendor Product Vulnerable Versions
XEN XEN 1

- References For CVE-2020-25597

https://xenbits.xen.org/xsa/advisory-338.html
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4JRXMKEMQRQYWYEPHVBIWUEAVQ3LU4FN/
FEDORA FEDORA-2020-306b84fd07
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DA633Y3G5KX7MKRN4PFEGM3IVTJMBEOM/
FEDORA FEDORA-2020-f668e579be
https://www.debian.org/security/2020/dsa-4769
DEBIAN DSA-4769
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00008.html
SUSE openSUSE-SU-2020:1608
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RJZERRBJN6E6STDCHT4JHP4MI6TKBCJE/
FEDORA FEDORA-2020-d46fe34349
https://security.gentoo.org/glsa/202011-06
GENTOO GLSA-202011-06

- Metasploit Modules Related To CVE-2020-25597

There are not any metasploit modules related to this CVE entry (Please visit www.metasploit.com for more information)


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