Vulnerability identifier: #VU48458

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26951

CWE-ID: CWE-20

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 vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to insufficient validation of user-supplied input. A parsing and event loading mismatch in Firefox's SVG code could have allowed load events to fire, even after sanitization. An attacker already capable of exploiting an XSS vulnerability in privileged internal pages could have used this attack to bypass the built-in sanitizer.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 60.9.0, 68.0 - 68.12.0, 78.0 - 78.4.1

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
http://www.mozilla.org/en-US/security/advisories/mfsa2020-51/

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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.