CVE-2020-26966 Information disclosure in Firefox

What is CVE-2020-26966?

CVE-2020-26966 is a medium-severity vulnerability in Mozilla Firefox, published on 9 Dec 2020. 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

Searching for a single word from the address bar caused an mDNS request to be sent on the local network searching for a hostname consisting of that string; resulting in an information leak. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

Which versions are affected by CVE-2020-26966?

It affects 3 products.

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

How do I fix CVE-2020-26966?

Upgrade to a fixed version.

Is CVE-2020-26966 being exploited?

There is no known exploitation of CVE-2020-26966 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-c627-2gcf-x56f, UBUNTU-CVE-2020-26966.