CVE-2026-4721
Critical · 9.8CVSS
9.8
EPSS
0.4%
Published
Mar 24, 2026
CISA due date
—
The record
Memory safety bugs present in Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148. 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 was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Chainguard | firefox | 0 | 149.0-r0 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| SUSE:Linux Enterprise Module for Desktop Applications 15 SP7 | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| SUSE:Linux Enterprise Server 15 SP4-LTSS | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| SUSE:Linux Enterprise Server 15 SP5-LTSS | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| SUSE:Linux Enterprise Server 15 SP6-LTSS | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| SUSE:Linux Enterprise Server for SAP Applications 15 SP4 | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| SUSE:Linux Enterprise Server for SAP Applications 15 SP5 | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| SUSE:Linux Enterprise Server for SAP Applications 15 SP6 | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| Wolfi | firefox | 0 | 149.0-r0 |
| openSUSE:Leap 15.6 | MozillaFirefox | 0 | 140.9.0-150200.152.225.1 |
| openSUSE:Leap 15.6 | MozillaThunderbird | 0 | 140.9.0-150200.8.263.1 |
| openSUSE:Leap 16.0 | MozillaFirefox | 0 | 140.9.0-160000.1.1 |
| openSUSE:Tumbleweed | MozillaFirefox | 0 | 149.0-1.1 |
| openSUSE:Tumbleweed | MozillaThunderbird | 0 | 140.9.0-1.1 |
| openSUSE:Tumbleweed | firefox-esr | 0 | 140.9.0-1.1 |
Related vulnerabilities
- CVE-2026-4726 Denial-of-service in the XML component. Also affects firefox
- CVE-2026-4724 Undefined behavior in the Audio/Video component. Also affects firefox
- CVE-2026-4729 Memory safety bugs present in Firefox 148 and Thunderbird 148. Also affects firefox
- CVE-2026-4722 Privilege escalation in the IPC component. Also affects firefox
- CVE-2026-4723 Use-after-free in the JavaScript Engine component. Also affects firefox
- CVE-2026-4727 Denial-of-service in the Libraries component in NSS. Also affects firefox
- CVE-2026-4728 Spoofing issue in the Privacy: Anti-Tracking component. Also affects firefox
- CVE-2026-4725 Sandbox escape due to use-after-free in the Graphics: Canvas2D component. Also affects firefox