CVE-2021-3930

An off-by-one error was found in the SCSI device emulation in QEMU. It could occur while processing MODE SELECT commands in mode_sense_page() if the 'page' argument was set to MODE_PAGE_ALLS (0x3f). A malicious guest could use this flaw to potentially crash QEMU, resulting in a denial of service condition.

Published: 2022-02-18 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-3930 is rated Low Risk (31.9/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.05%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-3930

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-12-03 0.03% 0.05% +0.02%
2 2025-11-21 0.06% 0.03% -0.02%
3 2025-11-18 — 0.06% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-3930

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.0 4.0 [email protected]
2.1 2.0 LOW
AV:L/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.9 2.9 [email protected]

Weakness enumeration for CVE-2021-3930

OS Trackers for CVE-2021-3930

vendor priority summary link
alpine medium CVE-2021-3930: 1 source package rows (qemu); 23 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 23. https://security.alpinelinux.org/vuln/CVE-2021-3930
debian not yet assigned CVE-2021-3930 not yet assigned priority: Debian including 1 source packages (qemu), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-3930
gentoo high CVE-2021-3930: 1 GLSA(s) (202208-27), 1 atom(s) (app-emulation/qemu); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-3930
redhat low — https://access.redhat.com/security/cve/CVE-2021-3930
suse low CVE-2021-3930 severity low: SUSE including 377 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 1859 product×package rows across 90 product lines (Container suse/sle-micro-rancher/5.2, HPE Helion OpenStack 8, … (90 product lines)): Known Not Affected 1460, Known Affected 231, Fixed 168. https://www.suse.com/security/cve/CVE-2021-3930/
ubuntu low CVE-2021-3930 low priority: Ubuntu including 1 source packages (qemu), 9 status rows across 9 suites (bionic, focal, hirsute, impish, jammy, kinetic, trusty, upstream, xenial): released 7, ignored 1, needs-triage 1. https://ubuntu.com/security/CVE-2021-3930

Affected software / configurations for CVE-2021-3930

Vendor Product Version Raw CPE
qemu qemu < 6.2.0 cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:*
redhat codeready_linux_builder 8.0 cpe:2.3:a:redhat:codeready_linux_builder:8.0:*:*:*:*:*:*:*
redhat codeready_linux_builder_for_ibm_z_systems 8.0 cpe:2.3:a:redhat:codeready_linux_builder_for_ibm_z_systems:8.0:*:*:*:*:*:*:*
redhat codeready_linux_builder_for_power_little_endian 8.0 cpe:2.3:a:redhat:codeready_linux_builder_for_power_little_endian:8.0:*:*:*:*:*:*:*
redhat openstack 10 cpe:2.3:a:redhat:openstack:10:*:*:*:*:*:*:*
redhat openstack 13 cpe:2.3:a:redhat:openstack:13:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux_advanced_virtualization_eus 8.4 cpe:2.3:o:redhat:enterprise_linux_advanced_virtualization_eus:8.4:*:*:*:*:*:*:*
redhat enterprise_linux_for_ibm_z_systems 8.0 cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:*
redhat enterprise_linux_for_power_little_endian 8.0 cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

References for CVE-2021-3930

cvelogic Threat Intelligence