Is CVE-2026-109737 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-109737 being exploited in the wild.

How severe is CVE-2026-109737?

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-2026-109737?

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-2026-109737?

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.

CVE-2026-109737: Firefox mitigation bypass in Enterprise Policies

CVE-2026-109737 · Severity: info · Published 2026-10-13

Firefox and Thunderbird's Enterprise Policies feature, which allows organizations to enforce security and configuration settings across their deployments, contains a bypass that could allow an attacker to circumvent these administrative controls. A successful exploit would undermine the organization's ability to enforce security policies on managed systems.

Technologies: Mozilla Firefox, Mozilla Firefox ESR, Mozilla Thunderbird, Mozilla Thunderbird ESR. Vendors: Mozilla.

Quick answers

Is CVE-2026-109737 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-109737 being exploited in the wild.
How severe is CVE-2026-109737?: 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-2026-109737?: 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.
How is CVE-2026-109737 attacked?: It is in a web application.
Am I affected by CVE-2026-109737?: 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

A mitigation bypass vulnerability exists in the Enterprise Policies component of Firefox and Thunderbird. The flaw allows policy enforcement to be circumvented through an unspecified mechanism in the policies validation logic. No CVSS score or detailed attack vector information is available from the advisory.

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

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