CVE-2020-15665: Mozilla Firefox

Medium severity, CVSS 4.3. EPSS: 0.7% chance of exploitation in the next 30 days.

Firefox did not reset the address bar after the beforeunload dialog was shown if the user chose to remain on the page. This could have resulted in an incorrect URL being shown when used in conjunction with other unexpected browser behaviors. This vulnerability affects Firefox < 80.

Affected products

• Mozilla Firefox: before 80.0 (fixed in 80.0)

Published 2020-10-01. Last modified 2026-06-17.