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Vulnerability · Published Sep 29, 2021 · Assigned by redhat

CVE-2021-3653

High 8.8

In plain English

A high-severity missing authorization in kernel. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)8.8High
Exploit odds (30 days)0.4%top 60.9% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:8kernel-tools-libs-devel4.18.0-305.19.1.el8_4ALSA-2021:3548
Debian:12linux5.14.6-1DEBIAN-CVE-2021-3653
Debian:13linux5.14.6-1DEBIAN-CVE-2021-3653
Debian:14linux5.14.6-1DEBIAN-CVE-2021-3653
Rocky Linux:8kernel0:4.18.0-305.19.1.el8_4RLSA-2021:3548
Rocky Linux:8kernel-rt0:4.18.0-305.19.1.rt7.91.el8_4RLSA-2021:3547
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2021-3653
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2021-3653
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2021-3653

Affected products (as reported)

VendorProductVersions
n/a kernel kernel 5.14-rc7

Weakness: CWE-862

References