Vulnerability identifier: #VU18903

Vulnerability risk: Medium

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-2019-12748

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
TYPO3
Web applications / CMS

Vendor: TYPO3

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 t3:// URL handling functionality. 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.

PoC:

t3://url/?url=javascript:alert(1);

Mitigation
Install updates from vendor's website.

Vulnerable software versions

TYPO3: 9.5.0 - 9.5.7, 9.0.0 - 9.4.0, 8.3.0 - 8.7.26

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External links
http://typo3.org/security/advisory/typo3-core-sa-2019-015/

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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.