VDB-186076 · CVE-2021-34866 · GCVE-0-2021-34866

Linux Kernel up to 5.13.13 eBPF kernel/bpf/verifier.c check_map_func_compatibility type confusion

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.
6.5	$0-$5k	0.00

Summaryinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 5.13.13. Affected by this vulnerability is the function check_map_func_compatibility of the file kernel/bpf/verifier.c of the component eBPF. Executing a manipulation can lead to type confusion. This vulnerability is handled as CVE-2021-34866. The attack can be executed remotely. Additionally, an exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 5.13.13 (Operating System). This vulnerability affects the function check_map_func_compatibility of the file kernel/bpf/verifier.c of the component eBPF. The manipulation with an unknown input leads to a type confusion vulnerability. The CWE definition for the vulnerability is CWE-843. The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was released 11/05/2021 by Ryota Shiga (@Ga_ryo_) with Flatt Security. The advisory is shared for download at blog.hexrabbit.io. This vulnerability was named CVE-2021-34866. Technical details and also a public exploit are known.

It is possible to download the exploit at github.com. It is declared as proof-of-concept. As 0-day the estimated underground price was around $5k-$25k.

Upgrading to version 5.13.14 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Operating System

Vendor

Linux

Name

Kernel

Version

License

open-source

Website

Vendor: https://www.kernel.org/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.2
VulDB Meta Temp Score: 6.5

VulDB Base Score: 7.2
VulDB Temp Score: 6.5
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: Type confusion
CWE: CWE-843
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Kernel 5.13.14
Patch: git.kernel.org

Timelineinfo

06/17/2021 🔍
11/05/2021 +141 days 🔍
11/05/2021 +0 days 🔍
11/09/2021 +4 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: blog.hexrabbit.io
Researcher: Ryota Shiga (@Ga_ryo_)
Organization: Flatt Security
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2021-34866 (🔍)
GCVE (CVE): GCVE-0-2021-34866
GCVE (VulDB): GCVE-100-186076
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 11/05/2021 01:00
Updated: 11/09/2021 20:05
Changes: 11/05/2021 01:00 (44), 11/05/2021 01:01 (1), 11/05/2021 01:05 (6), 11/09/2021 20:05 (1)
Complete: 🔍
Cache ID: 216::103