CVE-2020-29569: Use After Free
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.
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2020-29569?
The severity of CVE-2020-29569 is classified as moderate to high, depending on the specific environment and configuration.
How do I fix CVE-2020-29569?
To fix CVE-2020-29569, upgrade the affected package to version 5.10.223-1 or higher.
Which systems are affected by CVE-2020-29569?
CVE-2020-29569 affects specific versions of the Linux kernel from 4.1.44 up to 5.10.1, along with certain Xen releases.
What happens if CVE-2020-29569 is exploited?
Exploitation of CVE-2020-29569 could lead to a denial of service or potential information leakage in the affected systems.
Is there a workaround for CVE-2020-29569?
As an interim workaround for CVE-2020-29569, it is suggested to restrict the use of vulnerable versions until an update can be applied.