SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-28688

The lack of cleanup would result in leaking persistent grants.

MEDIUM 6.5EPSS 0.33%

Does this matter?

Lower severity and a low EPSS score (0.33%). Track it; it rarely justifies an emergency change on its own.

Description

The fix for 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. All Linux versions having the fix for XSA-365 applied are vulnerable. XSA-365 was classified to affect versions back to at least 3.11.

CVSS 3.1
6.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
EPSS
0.33% probability · 26th percentile
CISA KEV
Not listed
Weakness
CWE-665
Affected
linux/linux kernel · debian/debian linux
Source
security@xen.org

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.