PT-2026-27419 · Mozilla+1 · Firefox Esr+4
Christian Holler
+2
·
Published
2026-01-01
·
Updated
2026-04-17
·
CVE-2026-4721
CVSS v3.1
9.8
Critical
| Vector | AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Name of the Vulnerable Software and Affected Versions
Firefox versions prior to 149
Firefox ESR versions 115.33 through 140.8
Thunderbird versions prior to 149
Thunderbird ESR versions 140.8 through 140.9
Description
The software contains memory safety bugs, some of which demonstrate evidence of memory corruption. It is presumed that, with sufficient effort, these bugs could potentially be exploited to execute arbitrary code.
Recommendations
Update Firefox to version 149 or later.
Update Firefox ESR to version 115.34 or later, or version 140.9 or later.
Update Thunderbird to version 149 or later.
Update Thunderbird ESR to version 140.9 or later.
Fix
Buffer Overflow
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Weakness Enumeration
Related Identifiers
Affected Products
Firefox
Firefox Esr
Rocky Linux
Thunderbird
Thunderbird Esr