CVE-2026-6758

Received Received - Intake

Use-After-Free in Firefox WebAssembly Causes Potential Exploits

Publication date: 2026-04-21

Last updated on: 2026-04-22

Assigner: Mozilla Corporation

Description

Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-04-21

Last Modified

2026-04-22

Generated

2026-07-06

AI Q&A

2026-04-21

EPSS Evaluated

2026-07-05

NVD

CVE-2026-6758

EUVD

EUVD-2026-24099

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 150.0 (exc)
mozilla	thunderbird	to 150.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-416	The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

Executive Summary

This vulnerability is a use-after-free issue in the JavaScript WebAssembly component of Firefox. A use-after-free occurs when a program continues to use memory after it has been freed, which can lead to unexpected behavior or security risks.

The issue was addressed and fixed in Firefox version 150.

Impact Analysis

Exploitation of a use-after-free vulnerability in the WebAssembly component could potentially allow an attacker to execute arbitrary code, cause a crash, or manipulate the browser's behavior in unintended ways.

This could lead to security risks such as unauthorized access to information or system compromise if the vulnerability is exploited.

Mitigation Strategies

The vulnerability is fixed in Firefox 150. To mitigate this vulnerability, you should update your Firefox browser to version 150 or later.

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