REDHAT-BUG-2455901: High severity Mozilla Firefox vulnerability

Published Apr 7, 2026
·
Updated

Memory safety bugs present in Firefox ESR 115.34.0, Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1. 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 < 149.0.2, Firefox ESR < 115.34.1, and Firefox ESR < 140.9.1.

Affected Software

4 affected components
Mozilla Firefox<149.0.2
Mozilla Firefox ESR<115.34.1, <140.9.1
Mozilla Thunderbird=149.0.1
Mozilla Thunderbird ESR=140.9.0

Event History

Apr 7, 2026
Data Sourced
via Red Hat·01:01 PM
DescriptionSeverityAffected Software
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Frequently Asked Questions

1

What is the severity of REDHAT-BUG-2455901?

The severity of REDHAT-BUG-2455901 is considered high due to the potential for memory corruption and arbitrary code execution.

2

How do I fix REDHAT-BUG-2455901?

To fix REDHAT-BUG-2455901, update to the latest versions of Firefox and Thunderbird as specified in the advisory.

3

What versions are affected by REDHAT-BUG-2455901?

Affected versions include Firefox up to 149.0.2, Firefox ESR versions up to 115.34.1 and 140.9.1, and Thunderbird ESR 140.9.0.

4

Is REDHAT-BUG-2455901 specific to web browsers only?

Yes, REDHAT-BUG-2455901 specifically affects Mozilla Firefox and Thunderbird applications.

5

Can REDHAT-BUG-2455901 be exploited remotely?

While direct exploitation details are not confirmed, the memory safety bugs could potentially be exploited if exploited under the right conditions.

Contact

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