CVE-2020-15665

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-10-01 · updated 2026-06-17

Description

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

How to fix

Upgrade to a fixed version: Mozilla Firefox 80.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1651636
https://www.mozilla.org/security/advisories/mfsa2020-36/
https://bugzilla.mozilla.org/show_bug.cgi?id=1651636
https://www.mozilla.org/security/advisories/mfsa2020-36/

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