CVE-2021-38492 Security feature bypass in Firefox

What is CVE-2021-38492?

CVE-2021-38492 is a medium-severity vulnerability in Mozilla Firefox, published on 3 Nov 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

When delegating navigations to the operating system, Firefox would accept the `mk` scheme which might allow attackers to launch pages and execute scripts in Internet Explorer in unprivileged mode. *This bug only affects Firefox for Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 92, Thunderbird < 91.1, Thunderbird < 78.14, Firefox ESR < 78.14, and Firefox ESR < 91.1.

Which versions are affected by CVE-2021-38492?

It affects 3 products.

Products include Mozilla Firefox, Mozilla Firefox Esr, Mozilla Thunderbird.

How do I fix CVE-2021-38492?

Upgrade to a fixed version.

Is CVE-2021-38492 being exploited?

There is no known exploitation of CVE-2021-38492 in the wild and no public exploit code.

Other vulnerabilities in Mozilla Firefox

• CVE-2019-11708 Mozilla Firefox and Thunderbird Sandbox Escape Exploited Critical 10.0
• CVE-2010-3765 Mozilla Multiple Products Remote Code Execution Exploited Critical 9.8
• CVE-2022-26486 Mozilla Firefox Use-After-Free Exploited Critical 9.6
• CVE-2022-26485 Mozilla Firefox Use-After-Free Exploited High 8.8
• CVE-2019-11707 Mozilla Firefox and Thunderbird Type Confusion Exploited High 8.8

All Mozilla Firefox vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-qq3m-5g62-2hhj, UBUNTU-CVE-2021-38492.