CVE-2020-29569 Information

Description

An issue was discovered in the Linux kernel through 5.10.1 as used with Xen through 4.14.x. The Linux kernel PV block backend expects the kernel thread handler to reset ring->xenblkd to NULL when stopped. However the handler may not have time to run if the frontend quickly toggles between the states connect and disconnect. As a consequence the block backend may re-use a pointer after it was freed. A misbehaving guest can trigger a dom0 crash by continuously connecting / disconnecting a block frontend. Privilege escalation and information leaks cannot be ruled out. This only affects systems with a Linux blkback.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Reference

https://xenbits.xenproject.org/xsa/advisory-350.html https://www.debian.org/security/2021/dsa-4843 https://security.netapp.com/advisory/ntap-20210205-0001/ https://lists.debian.org/debian-lts-announce/2021/02/msg00018.html https://lists.debian.org/debian-lts-announce/2021/03/msg00010.html https://security.gentoo.org/glsa/202107-30

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.8