REDHAT-BUG-2428963: High severity Mozilla Firefox vulnerability

Published Jan 13, 2026
·
Updated

Memory safety bugs present in Firefox ESR 140.6, Thunderbird ESR 140.6, Firefox 146 and Thunderbird 146. 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 affects Firefox < 147 and Firefox ESR < 140.7.

Affected Software

4 affected components
Mozilla Firefox<147
Mozilla Firefox ESR<140.7
Mozilla Thunderbird<147
Mozilla Thunderbird ESR<140.7

Event History

Jan 13, 2026
Data Sourced
via Red Hat·02:01 PM
DescriptionSeverityAffected Software
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Frequently Asked Questions

1

What is the severity of REDHAT-BUG-2428963?

The severity of REDHAT-BUG-2428963 is high due to the potential for memory corruption leading to arbitrary code execution.

2

How do I fix REDHAT-BUG-2428963?

To fix REDHAT-BUG-2428963, upgrade to the latest versions of Firefox (147 and above) or Thunderbird (147 and above) as well as their ESR versions (140.7 and above).

3

Which versions are affected by REDHAT-BUG-2428963?

REDHAT-BUG-2428963 affects Firefox versions up to 146, Firefox ESR versions up to 140.6, Thunderbird versions up to 146, and Thunderbird ESR versions up to 140.6.

4

What kind of vulnerabilities does REDHAT-BUG-2428963 include?

REDHAT-BUG-2428963 includes memory safety bugs that can potentially lead to memory corruption.

5

Can REDHAT-BUG-2428963 be exploited?

Yes, with sufficient effort, the vulnerabilities in REDHAT-BUG-2428963 could potentially be exploited to execute arbitrary code.

Contact

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