CVE-2020-6810

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-03-25 · updated 2026-06-17
Weakness: CWE-290

Description

After a website had entered fullscreen mode, it could have used a previously opened popup to obscure the notification that indicates the browser is in fullscreen mode. Combined with spoofing the browser chrome, this could have led to confusing the user about the current origin of the page and credential theft or other attacks. This vulnerability affects Firefox < 74.

Affected products

Mozilla Firefox: before 74.0 — fixed in 74.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 74.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1432856
https://www.mozilla.org/security/advisories/mfsa2020-08/
https://bugzilla.mozilla.org/show_bug.cgi?id=1432856
https://www.mozilla.org/security/advisories/mfsa2020-08/

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