CVE-2026-16369

Analyzed Analyzed - Analysis Complete

Integer Overflow in Firefox JavaScript WebAssembly

Publication date: 2026-07-21

Last updated on: 2026-07-24

Assigner: Mozilla Corporation

Description

Integer overflow in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-07-21

Last Modified

2026-07-24

Generated

2026-08-10

AI Q&A

2026-07-21

EPSS Evaluated

2026-08-09

NVD

CVE-2026-16369

EUVD

EUVD-2026-46202

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 153.0.0 (exc)
mozilla	firefox	to 140.13.0 (exc)
mozilla	thunderbird	to 140.13.0 (exc)
mozilla	thunderbird	From 141.0 (inc) to 153.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-190	The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

Attack-Flow Graph

Executive Summary

This vulnerability is an integer overflow in the JavaScript WebAssembly component of Firefox. An integer overflow occurs when a calculation produces a result larger than the maximum value that can be stored in the variable's data type, potentially leading to unexpected behavior or crashes.

Detection Guidance

This vulnerability is specific to Firefox 153 and Firefox ESR 140.13. To detect it, check your installed Firefox version using commands like 'firefox --version' or 'about:support' in Firefox. If you are running an affected version, update immediately.

Impact Analysis

This vulnerability could allow an attacker to cause a crash or execute arbitrary code in the affected browser. Users running vulnerable versions of Firefox or Firefox ESR may be at risk of denial-of-service attacks or code execution by malicious websites.

Compliance Impact

The provided CVE data does not specify how this vulnerability impacts compliance with standards like GDPR or HIPAA. The description only mentions an integer overflow in the JavaScript WebAssembly component fixed in Firefox 153 and Firefox ESR 140.13.

Mitigation Strategies

Update Firefox to version 153 or later and Firefox ESR to version 140.13 or later to address the integer overflow in the JavaScript: WebAssembly component.

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