VulnTideExploited vulnerabilities, by vendor. Data as of .
Not in CISA KEVReported exploited: VulnCheck KEV since Published EPSS 1.4% probability of exploitation in 30 days
Mozilla

CVE-2020-15654: When in an endless loop, a website specifying a custom cursor using CSS could make it look like the user is interacti…

Is it exploited?

Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of .

VulnCheck KEV lists it since . It cites 1 public report, the first from .

How likely is exploitation in the next 30 days?
1.4%

EPSS score, percentile 72.8 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?
Not scored

The CVE record carries no CVSS score.

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (2)

Which versions are affected?

Affected

  • before 78.1
  • before 79
  • before 78.1

Versions by product

Source: CISA KEV 2026.10.29, as of ; VulnCheck KEV, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.

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.

Source: CVE List, as of . About the data.

What to do

Advisories and patches

This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Versions by product, as listed in the CVE record (3 products)
Mozilla Firefox ESR
StatusVersions
Affectedbefore 78.1
Mozilla Firefox
StatusVersions
Affectedbefore 79
Mozilla Thunderbird
StatusVersions
Affectedbefore 78.1

Source: CVE List, as of . About the data.

Timeline

DateEvent
CVE record published
CVE record last updated

References

4

Known exploited Mozilla vulnerabilities

  • CVE-2010-3765: Mozilla Multiple Products Remote Code Execution Vulnerability (added )
  • CVE-2024-9680: Mozilla Firefox Use-After-Free Vulnerability (added )
  • CVE-2016-9079: Mozilla Firefox, Firefox ESR, and Thunderbird Use-After-Free Vulnerability (added )
  • CVE-2015-4495: Mozilla Firefox Security Feature Bypass Vulnerability (added )
  • CVE-2019-11707: Mozilla Firefox and Thunderbird Type Confusion Vulnerability (added )