CVE-2026-12327
High
Description
Memory safety bugs present in Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151. 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 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
SeverityHigh
CVSS8.1
Exploit probability—
Product
Mozilla Firefox
PublishedJun 16, 2026
First seenJun 16, 2026
Weakness typeCWE-119Memory buffer bounds error
How to fix
Update
- mozilla firefox115.37.0, 152.0.0, 140.12.0 or later
- mozilla thunderbird152.0.0, 140.12.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 115.37.0, v < 152.0.0, 140.0 ≤ v < 140.12.0 | 115.37.0, 152.0.0, 140.12.0 |
| mozilla thunderbird | v < 152.0.0, 140.0 ≤ v < 140.12.0 | 152.0.0, 140.12.0 |
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