Description
Using the new logical assignment operators in a JavaScript switch statement could have caused a type confusion, leading to a memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.
References (4)
Core 4
Core References
Release Notes, Vendor Advisory x_refsource_misc
https://www.mozilla.org/security/advisories/mfsa2021-03/
Release Notes, Vendor Advisory x_refsource_misc
https://www.mozilla.org/security/advisories/mfsa2021-04/
Release Notes, Vendor Advisory x_refsource_misc
https://www.mozilla.org/security/advisories/mfsa2021-05/
Issue Tracking, Permissions Required, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/show_bug.cgi?id=1684020
Scores
CVSS v3
8.8
EPSS
0.0025
EPSS Percentile
48.5%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Details
CWE
CWE-843
Status
published
Products (3)
mozilla/firefox
< 85.0
mozilla/firefox_esr
< 78.7
mozilla/thunderbird
< 78.7
Published
Feb 26, 2021
Tracked Since
Feb 18, 2026