VDB-170265 · CVE-2021-27279 · GCVE-0-2021-27279

MyBB up to 1.8.24 MyCode cross site scripting

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.
4.3	$0-$5k	0.00

Summaryinfo

A vulnerability marked as problematic has been reported in MyBB up to 1.8.24. The impacted element is an unknown function of the component MyCode Handler. Performing a manipulation results in cross site scripting. This vulnerability is known as CVE-2021-27279. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in MyBB up to 1.8.24 (Content Management System). This affects an unknown code of the component MyCode Handler. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity.

The weakness was published 02/22/2021. The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2021-27279. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

Upgrading to version 1.8.25 eliminates this vulnerability. The upgrade is hosted for download at mybb.com. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Content Management System

Name

MyBB

Version

License

open-source

Website

Product: https://mybb.com/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.4
VulDB Meta Temp Score: 4.4

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.4
NVD Vector: 🔍

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: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Cross site scripting
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

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: MyBB 1.8.25
Patch: github.com

Timelineinfo

02/16/2021 🔍
02/22/2021 +6 days 🔍
02/22/2021 +0 days 🔍
03/04/2021 +10 days 🔍

Sourcesinfo

Product: mybb.com

Advisory: github.com
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2021-27279 (🔍)
GCVE (CVE): GCVE-0-2021-27279
GCVE (VulDB): GCVE-100-170265

Entryinfo

Created: 02/22/2021 23:06
Updated: 03/04/2021 10:31
Changes: 02/22/2021 23:06 (40), 03/04/2021 10:28 (6), 03/04/2021 10:31 (18)
Complete: 🔍
Cache ID: 216::103