Multiple vulnerabilities in Concrete CMS

Published: 2021-03-18

Risk	Low
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2021-28145 CVE-2021-3111
CWE-ID	CWE-79
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #2 is available.
Vulnerable software	concrete5 Web applications / CMS
Vendor	PortlandLabs

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Stored cross-site scripting

EUVDB-ID: #VU51576

Risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-28145

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 user to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data in Surveys functionality. A remote user with Editor privileges can inject 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

concrete5: 8.5.0 - 8.5.4

CPE2.3

External links

https://documentation.concrete5.org/developers/introduction/version-history/855-release-notes
https://www.concrete5.org/developers/security

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.

2) Cross-site scripting

EUVDB-ID: #VU51577

Risk: Low

CVSSv4.0: 2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:P/U:Clear]

CVE-ID: CVE-2021-3111

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 user to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data in express entries in index.php/dashboard/express/entries/view/ URI. A remote user can inject and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Mitigation

Install update from vendor's website.