How severe is CVE-2021-3947?

CVE-2021-3947 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-3947 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3947?

CVE-2021-3947 primarily affects Qemu. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-3947?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-3947 published?

CVE-2021-3947 was published on 2022-02-18 and last updated on 2026-06-17.

CVE-2021-3947

CVE-2021-3947 is a medium-severity vulnerability in Qemu with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v2: 2.1
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Qemu
Published: 2022-02-18
Last modified: 2026-06-17

Description

A stack-buffer-overflow was found in QEMU in the NVME component. The flaw lies in nvme_changed_nslist() where a malicious guest controlling certain input can read out of bounds memory. A malicious user could use this flaw leading to disclosure of sensitive information.

Frequently asked questions

What is CVE-2021-3947?: A stack-buffer-overflow was found in QEMU in the NVME component. The flaw lies in nvme_changed_nslist() where a malicious guest controlling certain input can read out of bounds memory. A malicious user could use this flaw leading to disclosure of sensitive information.
How severe is CVE-2021-3947?: CVE-2021-3947 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-3947 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3947?: CVE-2021-3947 primarily affects Qemu. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-3947?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-3947 published?: CVE-2021-3947 was published on 2022-02-18 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:*
cpe:2.3:a:qemu:qemu:6.2.0:rc0:*:*:*:*:*:*
cpe:2.3:a:qemu:qemu:6.2.0:rc1:*:*:*:*:*:*

More vulnerabilities in Qemu

CVE-2022-36648 — Critical (CVSS 10.0): The hardware emulation in the of_dpa_cmd_add_l2_flood of rocker device model in QEMU, as used in 7.0.0 and earlier,…
CVE-2017-16845 — Critical (CVSS 10.0): hw/input/ps2.c in Qemu does not validate 'rptr' and 'count' values during guest migration, leading to out-of-bounds…
CVE-2015-8556 — Critical (CVSS 10.0): Local privilege escalation vulnerability in the Gentoo QEMU package before 2.5.0-r1.
CVE-2009-3616 — Critical (CVSS 9.9): Multiple use-after-free vulnerabilities in vnc.c in the VNC server in QEMU 0.10.6 and earlier might allow guest OS…
CVE-2019-12929 — Critical (CVSS 9.8): The QMP guest_exec command in QEMU 4.0.0 and earlier is prone to OS command injection, which allows the attacker to…
CVE-2019-12928 — Critical (CVSS 9.8): The QMP migrate command in QEMU version 4.0.0 and earlier is vulnerable to OS command injection, which allows the…

All CVEs affecting Qemu →

Other CWE-125 (Out-of-bounds Read) vulnerabilities

CVE-2026-24826 — Critical (CVSS 10.0): Out-of-bounds Write, Divide By Zero, NULL Pointer Dereference, Use of Uninitialized Resource, Out-of-bounds Read,…
CVE-2024-22004 — Critical (CVSS 10.0): Due to length check, an attacker with privilege access on a Linux Nonsecure operating system can trigger a…
CVE-2021-41556 — Critical (CVSS 10.0): sqclass.cpp in Squirrel through 2.2.5 and 3.x through 3.1 allows an out-of-bounds read (in the core interpreter) that…
CVE-2021-21777 — Critical (CVSS 10.0): An information disclosure vulnerability exists in the Ethernet/IP UDP handler functionality of EIP Stack Group OpENer…
CVE-2017-14451 — Critical (CVSS 10.0): An exploitable out-of-bounds read vulnerability exists in libevm (Ethereum Virtual Machine) of CPP-Ethereum. A…
CVE-2013-0767 — Critical (CVSS 10.0): The nsSVGPathElement::GetPathLengthScale function in Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and…

Browse all CWE-125 (Out-of-bounds Read) vulnerabilities →