CVE-2020-29569

Public on 2021-01-25
Modified on 2021-01-26
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.
Severity
Important
CVSS v3 Base Score
8.8
See breakdown

Affected Packages

Platform Package Release Date Advisory
Amazon Linux 2 kernel 2021-01-25 23:09 ALAS2-2021-1588
Amazon Linux 1 kernel 2021-01-26 00:11 ALAS-2021-1477

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv2 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C
Amazon Linux CVSSv3 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD CVSSv2 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C
NVD CVSSv3 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H