# CVE-2026-92079: Mozilla Firefox mitigation bypass in Widget: Win32

Source: https://junglewise.ai/threats/cve-2026-92079-mozilla-firefox-mitigation-bypass-in-widget-win32  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-15. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-92079 · Severity: critical · CVSS 9.1 · Published 2026-09-15

Firefox is a widely-used web browser that millions rely on daily for secure web browsing. A mitigation bypass vulnerability in its Windows-specific component could allow an attacker to circumvent security protections built into the browser, potentially leading to unauthorized code execution or data compromise. Mozilla has patched this vulnerability in Firefox 156 and Firefox ESR 153.3.

Technologies: [Mozilla Firefox](https://junglewise.ai/threats/technologies/firefox), [Mozilla Firefox ESR](https://junglewise.ai/threats/technologies/firefox-esr), [Mozilla Thunderbird](https://junglewise.ai/threats/technologies/thunderbird), [Mozilla Thunderbird ESR](https://junglewise.ai/threats/technologies/thunderbird-esr). Vendors: [Mozilla](https://junglewise.ai/threats/vendors/mozilla).

## Quick answers

**Is CVE-2026-92079 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-92079 being exploited in the wild.

**How severe is CVE-2026-92079?** Critical severity, with a CVSS score of 9.1, published 15 September 2026.

**Which products and versions are affected?** Mozilla Firefox before 156; Mozilla Firefox ESR before 153.3; Mozilla Thunderbird before 156; Mozilla Thunderbird ESR before 153.3.

**Is there a fix for CVE-2026-92079?** A patch was published on 2026-09-15: Fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, Thunderbird 153.3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-92079 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-92079?** Check whether you run Mozilla Firefox, Mozilla Firefox ESR, Mozilla Thunderbird or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

This vulnerability is a mitigation bypass in Firefox's Widget: Win32 component, which handles Windows-specific UI and platform integration. A mitigation bypass allows an attacker to defeat security mechanisms (such as address space layout randomization, code signing verification, or sandboxing), potentially enabling arbitrary code execution or privilege escalation. The attack vector and specific preconditions are not disclosed in the available references, but the critical severity rating suggests network reachability and low user interaction friction. Mozilla released patches in Firefox 156 (release version) and Firefox ESR 153.3 (Extended Support Release).

## Affected products

- Mozilla Firefox before 156
- Mozilla Firefox ESR before 153.3
- Mozilla Thunderbird before 156
- Mozilla Thunderbird ESR before 153.3

## Timeline

- 2026-09-15: disclosed: Published as CVE-2026-92079
- 2026-09-15: patched: Fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, Thunderbird 153.3

## References

- [https://bugzilla.mozilla.org/show_bug.cgi?id=2067531](https://bugzilla.mozilla.org/show_bug.cgi?id=2067531)
- [https://www.mozilla.org/security/advisories/mfsa2026-90/](https://www.mozilla.org/security/advisories/mfsa2026-90/)

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