CVE-2021-28688 log

Source
Severity Low
Remote No
Type Denial of service
Description
A security issue was found in the Linux kernel before version 5.11.11, as used by Xen. The fix for CVE-2021-26930, a.k.a. XSA-365, includes initialization of pointers such that subsequent cleanup code wouldn't use uninitialized or stale values. This initialization went too far and may under certain conditions also overwrite pointers which are in need of cleaning up. The lack of cleanup would result in leaking persistent grants. The leak in turn would prevent fully cleaning up after a respective guest has died, leaving around zombie domains.
Group Package Affected Fixed Severity Status Ticket
AVG-1750 linux-lts 5.10.26-1 5.10.27-1 Medium Fixed
AVG-1749 linux-zen 5.11.10.zen1-1 5.11.11.zen1-1 Medium Fixed
AVG-1748 linux-hardened 5.11.10.hardened1-1 5.11.11.hardened1-1 Medium Fixed
AVG-1747 linux 5.11.10.arch1-1 5.11.11.arch1-1 Medium Fixed
References
https://xenbits.xen.org/xsa/advisory-371.html
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.11.11&id=632b046bb6120afe1df1bfa06943bee338dd97db
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.10.27&id=3a1ca9bd4f5a647439e82e07b03d072781d9d180
Notes
Workaround
==========

Avoiding the use of persistent grants will avoid the vulnerability. This can be achieved by passing the "feature_persistent=0" module option to the xen-blkback driver.