vulnerability
MFSA2021-11 Firefox: Security Vulnerabilities fixed in Firefox ESR 78.9 (CVE-2021-23987)
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 7 | (AV:N/AC:M/Au:N/C:P/I:P/A:P) | Mar 23, 2021 | Mar 24, 2021 | Aug 11, 2025 |
Severity
7
CVSS
(AV:N/AC:M/Au:N/C:P/I:P/A:P)
Published
Mar 23, 2021
Added
Mar 24, 2021
Modified
Aug 11, 2025
Description
Mozilla developers and community members reported memory safety bugs present in Firefox 86 and Firefox ESR 78.8. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.
Solution
mozilla-firefox-esr-upgrade-78_9
NEW
Explore Exposure Command
Confidently identify and prioritize exposures from endpoint to cloud with full attack surface visibility and threat-aware risk context.