CVE-2026-6755
Mitigation Bypass in Firefox DOM postMessage Component
Publication date: 2026-04-21
Last updated on: 2026-04-22
Assigner: Mozilla Corporation
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| mozilla | firefox | to 150.0 (exc) |
| mozilla | thunderbird | to 150.0 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-352 | The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a mitigation bypass in the DOM postMessage component of Mozilla Firefox. It means that a security measure intended to protect the postMessage functionality in the Document Object Model (DOM) could be circumvented by an attacker. The issue was fixed in Firefox version 150.
How can this vulnerability impact me? :
Exploitation of this vulnerability could allow an attacker to bypass security mitigations related to the postMessage component in Firefox. This might lead to unauthorized communication or data exchange between different origins in the browser, potentially exposing sensitive information or enabling further attacks.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability is fixed in Firefox version 150. Immediate mitigation should include updating Firefox to version 150 or later.