CVE-2026-2793
Critical
Description
Memory safety bugs present in Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147. 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 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
SeverityCritical
CVSS9.8
Exploit probability—
Product
Mozilla Firefox
PublishedFeb 24, 2026
First seenFeb 24, 2026
Weakness typeCWE-787Out-of-bounds write
How to fix
Update
- mozilla firefox115.33.0, 148.0, 140.8.0 or later
- mozilla thunderbird140.8.0, 148.0 or later
Vendor advisories
- access.redhat.com/errata/RHSA-2026:3984
- access.redhat.com/errata/RHSA-2026:3976
- access.redhat.com/errata/RHSA-2026:4260
- access.redhat.com/errata/RHSA-2026:3361
- access.redhat.com/errata/RHSA-2026:3517
- access.redhat.com/errata/RHSA-2026:3338
- access.redhat.com/errata/RHSA-2026:3515
- access.redhat.com/errata/RHSA-2026:3492
- access.redhat.com/errata/RHSA-2026:4432
- access.redhat.com/errata/RHSA-2026:3491
- access.redhat.com/errata/RHSA-2026:3980
- access.redhat.com/errata/RHSA-2026:3495
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 115.33.0, v < 148.0, 128.0 ≤ v < 140.8.0 | 115.33.0, 148.0, 140.8.0 |
| mozilla thunderbird | v < 140.8.0, v < 148.0 | 140.8.0, 148.0 |
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