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.
Advisories
Source ID Title
Debian DLA Debian DLA DLA-2557-1 linux-4.19 security update
Debian DLA Debian DLA DLA-2586-1 linux security update
Debian DSA Debian DSA DSA-4843-1 linux security update
EUVD EUVD EUVD-2020-21931 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.
Ubuntu USN Ubuntu USN USN-4749-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-4750-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-4751-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-4876-1 Linux kernel vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 16 Jul 2025 13:45:00 +0000

Type Values Removed Values Added
Metrics epss

{'score': 0.00173}

epss

{'score': 0.00123}


cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2024-08-04T16:55:10.494Z

Reserved: 2020-12-04T00:00:00

Link: CVE-2020-29569

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2020-12-15T17:15:14.707

Modified: 2024-11-21T05:24:13.443

Link: CVE-2020-29569

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.