VDB-195708 · CVE-2021-3748 · Nessus 209569

QEMU virtio-net Device num_buffers use after free

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.5	$0-$5k	0.00

Summaryinfo

A vulnerability, which was classified as problematic, was found in QEMU. The impacted element is an unknown function of the component virtio-net Device. The manipulation of the argument num_buffers results in use after free. This vulnerability was named CVE-2021-3748. There is no available exploit. It is advisable to implement a patch to correct this issue.

Detailsinfo

A vulnerability, which was classified as problematic, was found in QEMU (Virtualization Software) (affected version not known). Affected is some unknown functionality of the component virtio-net Device. The manipulation of the argument num_buffers with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on availability.

The weakness was presented 03/24/2022. The advisory is shared for download at bugzilla.redhat.com. This vulnerability is traded as CVE-2021-3748 since 08/30/2021. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 209569 (Oracle Linux 8 : virt:kvm_utils1 (ELSA-2024-12791)), which helps to determine the existence of the flaw in a target environment.

Applying the patch bedd7e93d01961fcb16a97ae45d93acf357e11f6 is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the vulnerability database at Tenable (209569). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Virtualization Software

Name

QEMU

License

open-source

Website

Product: https://www.qemu.org/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Partially

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 209569
Nessus Name: Oracle Linux 8 : virt:kvm_utils1 (ELSA-2024-12791)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Patch: bedd7e93d01961fcb16a97ae45d93acf357e11f6

Timelineinfo

08/30/2021 🔍
03/24/2022 +206 days 🔍
03/24/2022 +0 days 🔍
10/26/2024 +947 days 🔍

Sourcesinfo

Product: qemu.org

Advisory: bedd7e93d01961fcb16a97ae45d93acf357e11f6
Status: Confirmed

CVE: CVE-2021-3748 (🔍)
GCVE (CVE): GCVE-0-2021-3748
GCVE (VulDB): GCVE-100-195708

Entryinfo

Created: 03/24/2022 12:09
Updated: 10/26/2024 23:15
Changes: 03/24/2022 12:09 (40), 03/25/2022 16:41 (2), 03/25/2022 16:49 (1), 10/26/2024 23:15 (16)
Complete: 🔍
Cache ID: 216::103