Cross-site scripting in Mozilla bleach library

1) Cross-site scripting

EUVDB-ID: #VU25729

Risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/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-2020-6802

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. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code via calling "bleach.clean" with "noscript" and a raw tag in the "allowed/whitelisted" tags option 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

Bleach: 2.1 - 3.1.0

CPE2.3

• cpe:2.3:a:mozilla:bleach:2.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:bleach:2.1.1:*:*:*:*:*:*:*
• cpe:2.3:a:mozilla:bleach:2.1.2:*:*:*:*:*:*:*

External links

https://snyk.io/vuln/SNYK-PYTHON-BLEACH-552160
https://bugzilla.mozilla.org/show_bug.cgi?id=1615315
https://github.com/mozilla/bleach/commit/996cde7a2439a2323f9c4b2567c8b8449d393351
https://cure53.de/fp170.pdf
https://github.com/mozilla/bleach/releases/tag/v3.1.1

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.