HTML injection in Mozilla Firefox for Android

Published: 2021-04-19
Risk Low
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2021-29944
Exploitation vector Network
Public exploit N/A
Vulnerable software
Firefox for Android
Mobile applications / Apps for mobile phones

Vendor Mozilla

Security Advisory

This security advisory describes one low risk vulnerability.

1) Code Injection

Risk: Low

CVSSv3.1: 3.7 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-29944

CWE-ID: CWE-94 - Improper Control of Generation of Code ('Code Injection')

Exploit availability: No


The vulnerability allows a remote attacker to execute arbitrary HTML code.

The vulnerability exists due to improper input validation, when a webpage is viewed in Reader View. A remote attacker can inject and execute arbitrary HTML code in the victim's browser.


Install updates from vendor's website.

Vulnerable software versions

Firefox for Android: 80.1.2, 81.1.0, 81.1.3, 81.1.4, 81.1.5, 82.1.0, 82.1.1, 82.1.3, 83.0.0, 83.1.0, 84.1.0, 84.1.1, 84.1.2, 84.1.3, 84.1.4, 85.1.0, 85.1.1, 85.1.2, 85.1.3, 86.1.0, 86.1.1

CPE External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to open a a specially crafted app.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.