#VU53671 Stored cross-site scripting in Postbird - CVE-2021-33570

Vulnerability identifier: #VU53671

Vulnerability 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-2021-33570

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Postbird
Web applications / Modules and components for CMS

Vendor: Pavel Evstigneev

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 onerror attribute of an IMG element in any PostgreSQL database table. A remote authenticated attacker 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
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

Postbird: 0.1 - 0.8.4

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External links
https://github.com/Tridentsec-io/postbird
https://github.com/Paxa/postbird/issues/134
https://github.com/Paxa/postbird/issues/132
https://github.com/Paxa/postbird/issues/133
https://packetstormsecurity.com/files/162831/Postbird-0.8.4-Cross-Site-Scripting-Local-File-Inclusion.html

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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.