CVE-2026-2771
Modified Modified - Updated After Analysis

Undefined Behavior in Firefox DOM Core & HTML Components

Publication date: 2026-02-24

Last updated on: 2026-06-30

Assigner: Mozilla Corporation

Description
Undefined behavior in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

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Meta Information

Published
2026-02-24
Last Modified
2026-06-30
Generated
2026-07-06
AI Q&A
2026-02-24
EPSS Evaluated
2026-07-04
NVD
CVE-2026-2771

Affected Vendors & Products

Showing 5 associated CPEs
Vendor Product Version / Range
mozilla firefox to 148.0 (exc)
mozilla thunderbird to 148.0 (exc)
mozilla firefox to 115.33.0 (exc)
mozilla firefox From 128.0 (inc) to 140.8.0 (exc)
mozilla thunderbird to 140.8.0 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-125 The product reads data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

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Executive Summary

This vulnerability involves undefined behavior in the Document Object Model (DOM) within the Core and HTML components of Firefox. It affects versions of Firefox earlier than 148, as well as Firefox ESR versions earlier than 115.33 and 140.8.

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