# CVE-2026-92060: Mozilla Firefox use-after-free in Internationalization component

Source: https://junglewise.ai/threats/cve-2026-92060-mozilla-firefox-use-after-free-in-internationalization-component  
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-2026-92060 · Severity: high · CVSS 8.8 · Published 2026-09-15

Firefox, a widely-used web browser, contains a use-after-free vulnerability in its Internationalization component that can allow remote code execution when users visit malicious websites. This flaw could enable attackers to crash the browser or gain control of user systems and access sensitive data. The vulnerability has been patched in Firefox 156 and ESR versions.

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-2026-92060 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-92060 being exploited in the wild.

**How severe is CVE-2026-92060?** High severity, with a CVSS score of 8.8, 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-2026-92060?** A patch was published on 2026-09-15: Fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-92060 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-92060?** 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

A use-after-free vulnerability exists in Firefox's Internationalization (i18n) component, allowing memory safety violations when the browser processes certain internationalized content. The flaw is triggered through network attack vectors requiring user interaction (visiting a malicious webpage). An attacker can exploit this to achieve arbitrary code execution with the privileges of the user running Firefox. Mozilla has released patches in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3 to address this issue.

## 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
- 2026-09-15: patched: Fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3

## References

- [https://bugzilla.mozilla.org/show_bug.cgi?id=2027336](https://bugzilla.mozilla.org/show_bug.cgi?id=2027336)
- [https://www.mozilla.org/security/advisories/mfsa2026-90/](https://www.mozilla.org/security/advisories/mfsa2026-90/)

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