CVE-2022-34478: Mozilla Firefox

Medium severity, CVSS 6.5. EPSS: 0.8% chance of exploitation in the next 30 days.

The <code>ms-msdt</code>, <code>search</code>, and <code>search-ms</code> protocols deliver content to Microsoft applications, bypassing the browser, when a user accepts a prompt. These applications have had known vulnerabilities, exploited in the wild (although we know of none exploited through Thunderbird), so in this release Thunderbird has blocked these protocols from prompting the user to open them.<br>*This bug only affects Thunderbird on Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 102, Firefox ESR < 91.11, Thunderbird < 102, and Thunderbird < 91.11.

Affected products

• Mozilla Firefox: before 102.0 (fixed in 102.0)
• Mozilla Firefox ESR: before 91.11 (fixed in 91.11)
• Mozilla Thunderbird: before 91.11 (fixed in 91.11)

Published 2022-12-22. Last modified 2026-06-17.