Multiple vulnerabilities in MyBB

1) Cross-site scripting

EUVDB-ID: #VU51535

Risk: Low

CVSSv3.1: 5.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-27889

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: Yes

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data within the Nested Auto URL when parsing messages. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation

Install update from vendor's website.

Vulnerable software versions

MyBB: 1.8.0 - 1.8.25

External links

http://github.com/mybb/mybb/security/advisories/GHSA-xhj7-3349-mqcm

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

2) SQL injection

EUVDB-ID: #VU51539

Risk: High

CVSSv3.1: 8.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-27890

CWE-ID: CWE-89 - Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to execute arbitrary SQL queries in database.

The vulnerability exists due to insufficient sanitization of user-supplied data within the theme properties included in theme XML files. A remote attacker can send a specially crafted request to the affected application and execute arbitrary SQL commands within the application database.

Successful exploitation of this vulnerability may allow a remote attacker to read, delete, modify data in database and gain complete control over the affected application.

Mitigation

Cybersecurity Help is currently unaware of any official solution to address this vulnerability..

Vulnerable software versions

MyBB: 1.8.0 - 1.8.25

External links

http://github.com/mybb/mybb/security/advisories/GHSA-r34m-ccm8-mfhq

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

3) SQL injection

EUVDB-ID: #VU51538

Risk: Medium

CVSSv3.1: 7.9 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-27946

CWE-ID: CWE-89 - Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to execute arbitrary SQL queries in database.

The vulnerability exists due to insufficient sanitization of user-supplied data in the poll vote count. A remote authenticated attacker can send a specially crafted request to the affected application and execute arbitrary SQL commands within the application database.

Successful exploitation of this vulnerability may allow a remote attacker to read, delete, modify data in database and gain complete control over the affected application.

Mitigation

Install update from vendor's website.

Vulnerable software versions

MyBB: 1.8.0 - 1.8.25

External links

http://github.com/mybb/mybb/security/advisories/GHSA-23m9-w75q-ph4p

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

4) SQL injection

EUVDB-ID: #VU51537

Risk: Low

CVSSv3.1: 6.3 [CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-27947

CWE-ID: CWE-89 - Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')

Exploit availability: No

Description

The vulnerability allows a remote user to execute arbitrary SQL queries in database.

The vulnerability exists due to insufficient sanitization of user-supplied data within the Copy Forum feature in Forum Management. A remote administrator can send a specially crafted request to the affected application and execute arbitrary SQL commands within the application database.

Successful exploitation of this vulnerability may allow a remote attacker to read, delete, modify data in database and gain complete control over the affected application.

Mitigation

Install update from vendor's website.

Vulnerable software versions

MyBB: 1.8.0 - 1.8.25

External links

http://github.com/mybb/mybb/security/advisories/GHSA-jjx8-8mcp-7h65

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated privileged user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

5) Cross-site scripting

EUVDB-ID: #VU51536

Risk: Low

CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-27949

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: No

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data in the Custom moderator tools. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

MyBB: 1.8.0 - 1.8.25

External links

http://github.com/mybb/mybb/security/advisories/GHSA-cmmr-39v8-8rx2

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

6) SQL injection

EUVDB-ID: #VU51540

Risk: Low

CVSSv3.1: 6.3 [CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-27948

CWE-ID: CWE-89 - Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')

Exploit availability: No

Description

The vulnerability allows a remote user to execute arbitrary SQL queries in database.

The vulnerability exists due to insufficient sanitization of user-supplied data in the User Groups. A remote administrator can send a specially crafted request to the affected application and execute arbitrary SQL commands within the application database.

Successful exploitation of this vulnerability may allow a remote attacker to read, delete, modify data in database and gain complete control over the affected application.

Mitigation

Install update from vendor's website.

Vulnerable software versions

MyBB: 1.8.0 - 1.8.25

External links

http://github.com/mybb/mybb/security/advisories/GHSA-3p9w-2q65-r6g2

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated privileged user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.