Vulnerability in Mozilla Firefox

CVE-2020-15654

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.

EPSS: 0.012 (65.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2020-15654?
CVE-2020-15654 is a medium-severity vulnerability in Mozilla Firefox, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 6.5/10. Published 2020-08-10.
How severe is CVE-2020-15654?
Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2020-15654 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.