Mozilla Firefox ESR (rm) 140.10.0
Mozilla Firefox ESR (rm) 140.10.0, released April 21, 2026, fixes 1 CVE in Mozilla Firefox ESR (rm). None of them is reported as exploited. Patch Radar priority: High. The latest Mozilla Firefox ESR (rm) is 153.6.0, which also fixes every one of these CVEs.
Superseded. The latest Mozilla Firefox ESR (rm) is 153.6.0, which also fixes every CVE on this page. Install that instead.
Applies to
| Product | Version |
|---|---|
| Mozilla Firefox ESR (rm) | 140.10.0 |
CVEs this fix closes
| Priority | CVE | Title | CVSS | EPSS | Exploitation |
|---|---|---|---|---|---|
| High | CVE-2026-5731 | Memory safety bugs fixed in Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2 | 9.8 | 0.0035 | None reported |
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