Multiple vulnerabilities in Joomla!

1) Cross-site scripting

EUVDB-ID: #VU54579

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-2021-26039

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 com_media component. 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

Joomla!: 3.0.0 - 3.9.27

External links

http://developer.joomla.org/security-centre/860-20210705-core-xss-in-com-media-imagelist.html

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.

2) Improper access control

EUVDB-ID: #VU54578

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-26038

CWE-ID: CWE-284 - Improper Access Control

Exploit availability: No

Description

The vulnerability allows a remote user to gain unauthorized access to otherwise restricted functionality.

The vulnerability exists due to improper access restrictions within the com_installer component. the iInstall action in com_installer lacks the required hardcoded ACL checks for superusers. A remote unprivileged user can compromise the affected installation of Joomla! under certain circumstances.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Joomla!: 2.5.0 - 3.9.27

External links

http://developer.joomla.org/security-centre/859-20210704-core-privilege-escalation-through-com-installer.html

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.

3) Insufficient Session Expiration

EUVDB-ID: #VU54577

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-26037

CWE-ID: CWE-613 - Insufficient Session Expiration

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to insufficient session expiration issue when changing user's password or blocking the user accont. A remote non-authenticated attacker can obtain or guess session token and gain unauthorized access to session that belongs to another user.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Joomla!: 2.5.0 - 3.9.27

External links

http://developer.joomla.org/security-centre/858-20210703-core-lack-of-enforced-session-termination.html

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.

4) Input validation error

EUVDB-ID: #VU54576

Risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-26036

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote user to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input. A remote user can pass specially crafted input to the application and damage usergroups table, leading to a denial of service condition.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Joomla!: 2.5.0 - 3.9.27

External links

http://developer.joomla.org/security-centre/857-20210702-core-dos-through-usergroup-table-manipulation.html

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.

5) Cross-site scripting

EUVDB-ID: #VU54575

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-2021-26035

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 Rules field of the JForm API. 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

Joomla!: 3.0.0 - 3.9.27

External links

http://developer.joomla.org/security-centre/856-20210701-core-xss-in-jform-rules-field.html

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.