Information disclosure in Firefox ESR and Mozilla Firefox - CVE-2020-26966

Vulnerability details

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to the way Firefox performs searches of single-word queries. Searching for a single word from the address bar cause an mDNS request to be sent on the local network searching for a hostname consisting of that string. A remote attacker with the local network can intercept the DNS query and obtain information, searched via browser address bar.

Note, the vulnerability affects Windows users only.

Affected software

How to mitigate CVE-2020-26966

External References

• https://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
• https://www.mozilla.org/en-US/security/advisories/mfsa2020-51/

Related Security Bulletins

• Multiple vulnerabilities in Mozilla Firefox and Firefox ESR
• Multiple vulnerabilities in Mozilla Thunderbird
• Multiple vulnerabilities in Firefox for Android
• Information disclosure in firefox-esr (Alpine package)
• Information disclosure in firefox (Alpine package)
• Information disclosure in thunderbird (Alpine package)