#VU24060 Cross-site scripting in Mozilla Firefox and Firefox ESR - CVE-2019-17022

Vulnerability identifier: #VU24060

Vulnerability risk: Medium

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:Green]

CVE-ID: CVE-2019-17022

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Mozilla Firefox
Client/Desktop applications / Web browsers
Firefox ESR
Client/Desktop applications / Web browsers

Vendor: Mozilla

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 CSS sanitizer. When pasting a tag from the clipboard into a rich text editor, the CSS sanitizer does not escape < and > characters. If a webpage subsequently copies the node's innerHTML, assigning it to another innerHTML, this would result in an XSS vulnerability.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 65.0 - 71.0

Firefox ESR: 60.0 - 60.9.0, 68.0 - 68.3.0

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External links
https://www.mozilla.org/en-US/security/advisories/mfsa2020-01/

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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.