CVE-2026-109739 Details
Description
Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.
A privilege escalation vulnerability has been identified in the WebExtensions component of Mozilla Firefox and Thunderbird. This issue allows for elevated privileges within the application, potentially leading to unauthorized actions or access. The vulnerability affects Firefox and Thunderbird versions prior to 158.
Users can upgrade to Firefox or Thunderbird version 158 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Oct 13, 2026CISA-ADP
Assessed Oct 14, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://bugzilla.mozilla.org/show_bug.cgi?id=2049069 | [email protected] | Issue TrackingPermission RequiredVendor |
| https://www.mozilla.org/security/advisories/mfsa2026-106/ | [email protected] | AdvisoryBundleVendor |
| https://www.mozilla.org/security/advisories/mfsa2026-109/ | [email protected] | AdvisoryBundleVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-269 | Improper Privilege Management | CISA-ADP |
Affected Products
| Product | Versions |
|---|---|
| Mozilla Firefox | All versions |
CPE
Remediation
| |
| Mozilla Thunderbird | All versions |
CPE
Remediation
| |
Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Oct 14, 2026 | CVE Modified | CISA-ADP |
| Oct 14, 2026 | CVE Modified | CISA-ADP |
| Oct 14, 2026 | CVE Modified | CISA-ADP |
| Oct 13, 2026 | CVE Modified | [email protected] |
| Oct 13, 2026 | New CVE Received | [email protected] |