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CVE-2020-11742

Published: 14 April 2020

An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service because of bad continuation handling in GNTTABOP_copy. Grant table operations are expected to return 0 for success, and a negative number for errors. The fix for CVE-2017-12135 introduced a path through grant copy handling where success may be returned to the caller without any action taken. In particular, the status fields of individual operations are left uninitialised, and may result in errant behaviour in the caller of GNTTABOP_copy. A buggy or malicious guest can construct its grant table in such a way that, when a backend domain tries to copy a grant, it hits the incorrect exit path. This returns success to the caller without doing anything, which may cause crashes or other incorrect behaviour.

Notes

AuthorNote
mdeslaur
hypervisor packages are in universe. For
issues in the hypervisor, add appropriate
tags to each section, ex:
Tags_xen: universe-binary

Priority

Medium

Cvss 3 Severity Score

5.5

Score breakdown

Status

Package Release Status
xen
Launchpad, Ubuntu, Debian
bionic Needed

eoan Ignored
(end of life)
trusty Does not exist

upstream Needs triage

hirsute Ignored
(end of life)
groovy Ignored
(end of life)
xenial Needed

jammy Not vulnerable
(4.11.4-1)
lunar Not vulnerable
(4.11.4-1)
focal
Released (4.11.3+24-g14b62ab3e5-1ubuntu2.3)
impish Ignored
(end of life)
kinetic Not vulnerable
(4.11.4-1)
mantic Not vulnerable
(4.11.4-1)
Binaries built from this source package are in Universe and so are supported by the community.

Severity score breakdown

Parameter Value
Base score 5.5
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H