CVE-2020-26979

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-01-07 · updated 2026-06-17
Weakness: CWE-601

Description

When a user typed a URL in the address bar or the search bar and quickly hit the enter key, a website could sometimes capture that event and then redirect the user before navigation occurred to the desired, entered address. To construct a convincing spoof the attacker would have had to guess what the user was typing, perhaps by suggesting it. This vulnerability affects Firefox < 84.

Affected products

Mozilla Firefox: before 84.0 — fixed in 84.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 84.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1641287%2C1673299
https://www.mozilla.org/security/advisories/mfsa2020-54/
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1641287%2C1673299
https://www.mozilla.org/security/advisories/mfsa2020-54/

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