Out-of-bounds Read in Linux Kernel
CVE-2021-4093
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.
Vulnerability class: Buffer Overflow
EPSS: 0.004 (34.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
Affected products
- Linux Linux_kernel
- Canonical Ubuntu_linux — versions 20.04, 21.10
- Fedoraproject Fedora — versions 35
- Redhat Enterprise_linux — versions 8.0
- N/a Kernel — versions kernel 5.15
Weakness classification (CWE)
Public proof-of-concept exploits
References
- secalert@redhat.com (Patch, Third Party Advisory, x_refsource_MISC, Issue Tracking)
- secalert@redhat.com (Exploit, Patch, Mailing List, Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2021-4093?
- CVE-2021-4093 is a high-severity vulnerability in Linux Kernel, classified under Out-of-bounds Read. CVSS score: 8.8/10. Published 2022-02-18.
- How severe is CVE-2021-4093?
- High severity. CVSS v3 base score is 8.8 out of 10.
- Is CVE-2021-4093 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.