CVE-2017-7840: Mozilla Firefox

Medium severity, CVSS 6.1. EPSS: 1.1% chance of exploitation in the next 30 days.

JavaScript can be injected into an exported bookmarks file by placing JavaScript code into user-supplied tags in saved bookmarks. If the resulting exported HTML file is later opened in a browser this JavaScript will be executed. This could be used in social engineering and self-cross-site-scripting (self-XSS) attacks if users were convinced to add malicious tags to bookmarks, export them, and then open the resulting file. This vulnerability affects Firefox < 57.

Affected products

• Mozilla Firefox: up to and including 56.0.2

Published 2018-06-11. Last modified 2026-06-17.