CVE-2020-15665

Name: CVE-2020-15665
Creator: NVD / NIST
Published: 2020-10-01T19:15:13.127+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.3/10EPSS 0.68%

Last modified Jun 17, 2026

CVE-2020-15665 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. 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. EPSS estimates a 0.68% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

4.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

EPSS Probability

0.68%

47.6th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 80.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1651636Exploit, Issue Tracking, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-36/Release Notes, Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1651636Exploit, Issue Tracking, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-36/Release Notes, Vendor Advisory

Timeline

Published: Oct 1, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-15665?

How severe is CVE-2020-15665?

CVE-2020-15665 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.68% probability of exploitation in the next 30 days.

How do I fix CVE-2020-15665?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-15665?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST