🛡️ CVE-2021-3653 on Debian — linux

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

Description

A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the "int_ctl" field, this issue could allow a malicious L1 to enable AVIC support (Advanced Virtual Interrupt Controller) for the L2 guest. As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape. This flaw affects Linux kernel versions prior to 5.14-rc7.

Distribution advisory

This page covers CVE-2021-3653 as tracked by Debian, for the package linux. The fix is available in version 5.14.6-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality high, integrity high, availability high.

Affected software

DEBIAN-CVE-2021-3653 is recorded against 1 package.

linux (fixed in 5.14.6-1)

Timeline and source

Published on 29 September 2021 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2021-3653 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Ubuntu

Details

Severity Unknown

CVSS Score N/A

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

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2021-09-29

Updated 2026-08-12

Modified 2026-08-04

Fix URL N/A

Affected Packages

Software	From version	Fixed in
linux	—	5.14.6-1

References

ADVISORY https://security-tracker.debian.org/tracker/CVE-2021-3653

🔗 NVD 🔗 Mitre

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