Vulnerability · Published Feb 18, 2022 · Assigned by redhat

CVE-2021-4093

High 8.8

In plain English

A high-severity out-of-bounds read 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 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)8.8High

Exploit odds (30 days)0.4%top 63.6% 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 the Secure Encrypted Virtualization-Encrypted State (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kernel via a malicious VMGEXIT for a string I/O instruction (for example, outs or ins) using the exit reason SVM_EXIT_IOIO. This issue results in a crash of the entire system or a potential guest-to-host escape scenario.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	linux	5.14.16-1	DEBIAN-CVE-2021-4093
Debian:13	linux	5.14.16-1	DEBIAN-CVE-2021-4093
Debian:14	linux	5.14.16-1	DEBIAN-CVE-2021-4093
Rocky Linux:8	kernel	0:4.18.0-372.9.1.el8	RLSA-2022:1988

Affected products (as reported)

Vendor	Product	Versions
n/a	kernel	kernel 5.15

Weakness: CWE-125

References

https://bugzilla.redhat.com/show_bug.cgi?id=2028584 x_refsource_MISC
https://bugs.chromium.org/p/project-zero/issues/detail?id=2222 x_refsource_MISC