CVE-2020-6798: Mozilla Firefox

Medium severity, CVSS 6.1. EPSS: 2.1% chance of exploitation in the next 30 days.

If a template tag was used in a select tag, the parser could be confused and allow JavaScript parsing and execution when it should not be allowed. A site that relied on the browser behaving correctly could suffer a cross-site scripting vulnerability as a result. In general, this flaw cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but is potentially a risk in browser or browser-like contexts. This vulnerability affects Thunderbird < 68.5, Firefox < 73, and Firefox < ESR68.5.

Affected products

• Mozilla Firefox: before 73.0 (fixed in 73.0)
• Mozilla Firefox ESR: before 68.5.0 (fixed in 68.5.0)
• Mozilla Thunderbird: before 68.5.0 (fixed in 68.5.0)

Published 2020-03-02. Last modified 2026-06-17.