CVE-2026-5734
Critical · 9.8CVSS
9.8
EPSS
0.6%
Published
Apr 7, 2026
CISA due date
—
The record
Memory safety bugs present in Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1. 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 149.0.2, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| openSUSE:Leap 16.0 | MozillaFirefox | 0 | 140.9.1-160000.1.1 |
| openSUSE:Tumbleweed | MozillaFirefox | 0 | 149.0.2-1.1 |
| openSUSE:Tumbleweed | MozillaThunderbird | 0 | 140.9.1-1.1 |
| openSUSE:Tumbleweed | firefox-esr | 0 | 140.9.1-1.1 |
Related vulnerabilities
- CVE-2026-12324 Incorrect boundary conditions in the Graphics: CanvasWebGL component. Also affects MozillaFirefox
- CVE-2026-12325 Denial-of-service in the Graphics: ImageLib component. Also affects MozillaFirefox
- CVE-2026-12327 Memory safety bugs present in Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151 and… Also affects MozillaFirefox
- CVE-2026-12330 Incorrect boundary conditions in the Internationalization component. Also affects MozillaFirefox
- CVE-2026-12329 Memory safety bug fixed in Thunderbird ESR 140.12. Also affects MozillaFirefox
- CVE-2026-12328 Memory safety bugs present in Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird ESR… Also affects MozillaFirefox
- CVE-2026-12315 Mitigation bypass in the DOM: Security component. Also affects MozillaFirefox
- CVE-2026-12314 Memory safety bug fixed in Thunderbird 152. Also affects MozillaFirefox