CVE-2020-15654

Name: CVE-2020-15654
Creator: NVD / NIST
Published: 2020-08-10T18:15:12.437+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.24%

Last modified Jun 17, 2026

CVE-2020-15654 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. When in an endless loop, a website specifying a custom cursor using CSS could make it look like the user is interacting with the user interface, when they are not. This could lead to a perceived broken state, especially when interactions with existing browser dialogs and warnings do not work. EPSS estimates a 1.24% chance of exploitation in the next 30 days.

Description

When in an endless loop, a website specifying a custom cursor using CSS could make it look like the user is interacting with the user interface, when they are not. This could lead to a perceived broken state, especially when interactions with existing browser dialogs and warnings do not work. This vulnerability affects Firefox ESR < 78.1, Firefox < 79, and Thunderbird < 78.1.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

1.24%

65.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-835

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 79.0
Mozilla	Firefox Esr	< 78.1
Mozilla	Thunderbird	< 78.1
Canonical	Ubuntu Linux	16.04
Canonical	Ubuntu Linux	18.04
Canonical	Ubuntu Linux	20.04

References

http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00025.htmlThird Party Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1648333Issue Tracking, Vendor Advisory
https://usn.ubuntu.com/4443-1/Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2020-30/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-32/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-33/Vendor Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00025.htmlThird Party Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1648333Issue Tracking, Vendor Advisory
https://usn.ubuntu.com/4443-1/Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2020-30/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-32/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-33/Vendor Advisory

Timeline

Published: Aug 10, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-15654?

How severe is CVE-2020-15654?

CVE-2020-15654 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.24% probability of exploitation in the next 30 days.

How do I fix CVE-2020-15654?

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-2020-15654?

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

Scan your code now

Source: NVD / NIST