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CVE-2021-28688

MEDIUMCVSS 6.5/10EPSS 0.33%

Last modified

CVE-2021-28688 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 0.33% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
6.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

EPSS Probability
0.33%

24.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
LinuxLinux Kernel>= 3.11, <= 5.10.18
DebianDebian Linux9.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-28688?
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.
How severe is CVE-2021-28688?
CVE-2021-28688 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.33% probability of exploitation in the next 30 days.
How do I fix CVE-2021-28688?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-28688?

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Source: NVD / NIST