#VU51777 Cross-site scripting in Lxml - CVE-2021-28957
Published: March 30, 2021
Vulnerability identifier: #VU51777
Vulnerability risk: Low
CVSSv4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear
CVE-ID: CVE-2021-28957
CWE-ID: CWE-79
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Lxml
Lxml
Software vendor:
Lxml
Lxml
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. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. 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.
Remediation
Install updates from vendor's website.