# CVE-2026-109764: Mozilla Firefox Enterprise Policies mitigation bypass

Source: https://junglewise.ai/threats/cve-2026-109764-mitigation-bypass-in-the-enterprise-policies-component-this  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-109764 · Severity: info · Published 2026-10-13

A mitigation bypass vulnerability exists in Firefox's Enterprise Policies component, which is used to enforce security policies in business deployments. An attacker who can interact with an affected system may bypass intended security mitigations, potentially leading to further exploitation. The vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

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-2026-109764 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-109764 being exploited in the wild.

**How severe is CVE-2026-109764?** Informational severity, published 13 October 2026.

**Which products and versions are affected?** Mozilla Firefox before 158; Mozilla Firefox ESR before 153.5; Mozilla Thunderbird before 158; Mozilla Thunderbird ESR before 153.5.

**Is there a fix for CVE-2026-109764?** Yes: fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird ESR 153.5. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2026-109764?** 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.

## How to fix

- Fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird ESR 153.5

## Technical details

This mitigation bypass in the Enterprise Policies component allows attackers to circumvent security controls intended to prevent exploitation or enforce policy compliance. The vulnerability affects Firefox, Firefox ESR, Thunderbird, and Thunderbird ESR. Mozilla has addressed this issue in the specified versions.

## Affected products

- Mozilla Firefox before 158
- Mozilla Firefox ESR before 153.5
- Mozilla Thunderbird before 158
- Mozilla Thunderbird ESR before 153.5

## Timeline

- 2026-10-13: disclosed

## References

- [https://bugzilla.mozilla.org/show_bug.cgi?id=2073382](https://bugzilla.mozilla.org/show_bug.cgi?id=2073382)
- [https://www.mozilla.org/security/advisories/mfsa2026-106/](https://www.mozilla.org/security/advisories/mfsa2026-106/)

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