Unchecked Return Value Affecting linux-4.19 package, versions <4.19.171-2~deb9u1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.05% (17th percentile)

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  • Snyk IDSNYK-DEBIAN9-LINUX419-1073741
  • published16 Dec 2020
  • disclosed15 Dec 2020

Introduced: 15 Dec 2020

CVE-2020-29569  (opens in a new tab)
CWE-252  (opens in a new tab)

How to fix?

Upgrade Debian:9 linux-4.19 to version 4.19.171-2~deb9u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-4.19 package and not the linux-4.19 package as distributed by Debian. See How to fix? for Debian:9 relevant fixed versions and status.

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 Base Scores

version 3.1