Cyber Resilience

CVE-2021-28688

Medium

Published: 06 April 2021

Published
06 April 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 6.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.0013 32.5th percentile
Risk Priority 13 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-28688 is a medium-severity Improper Initialization (CWE-665) vulnerability in Linux Linux Kernel. Its CVSS base score is 6.5 (Medium).

Operationally, ranked at the 32.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

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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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

linux
linux kernel
3.11 — 5.10.18
debian
debian linux
9.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-665

Ensures shared resources are explicitly initialized or cleared on allocation, preventing exposure of prior contents to new users or processes.

addresses: CWE-665

Mandates that every instance begins in a known (presumably clean) state, eliminating reliance on residual or uninitialized state left by prior executions.

References