Vulnerability identifier: #VU49942

Vulnerability risk: Low

CVSSv3.1: 4.6 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-27674

CWE-ID: CWE-119

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Xen
Server applications / Virtualization software

Vendor: Xen Project

Description

The vulnerability allows a local authenticated user to read and manipulate data.

An issue was discovered in Xen through 4.14.x allowing x86 PV guest OS users to gain guest OS privileges by modifying kernel memory contents, because invalidation of TLB entries is mishandled during use of an INVLPG-like attack technique.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Xen: 4.0.0 - 4.14.1

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External links
http://www.openwall.com/lists/oss-security/2021/01/19/5
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PZAM3LYJ5TZLSSNL3KXFILM46QKVTOUA/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U3U4LNKKXU4UP4Z5XP6TMIWSML3QODPE/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XIK57QJOVOPWH6RFRNMGOBCROBCKMDG2/
http://security.gentoo.org/glsa/202011-06
http://www.debian.org/security/2020/dsa-4804
http://xenbits.xen.org/xsa/advisory-286.html

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.