CVE-2026-109763 Details
Description
Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
A mitigation bypass vulnerability has been identified in the File Handling component of Mozilla Firefox and Thunderbird. This vulnerability allows for the circumvention of existing safeguards, potentially leading to unintended behavior or exploitation. It affects Firefox versions prior to 158, Firefox ESR through 153.5, Thunderbird versions prior to 158, and Thunderbird ESR through 153.5.
Users can upgrade to Firefox 158, Firefox ESR 153.5, Thunderbird 158, or Thunderbird ESR 153.5 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 19, 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=2072501 | [email protected] | Issue TrackingPermission RequiredVendor |
| https://www.mozilla.org/security/advisories/mfsa2026-106/ | [email protected] | AdvisoryBundleVendor |
| https://www.mozilla.org/security/advisories/mfsa2026-108/ | [email protected] | AdvisoryBundleVendor |
| https://www.mozilla.org/security/advisories/mfsa2026-109/ | [email protected] | AdvisoryBundleVendor |
| https://www.mozilla.org/security/advisories/mfsa2026-110/ | [email protected] | AdvisoryBundleVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-20 | Improper Input Validation | CISA-ADP |
Affected Products
| Product | Versions |
|---|---|
| Mozilla Firefox | All versions |
CPE
Remediation
| |
| Mozilla Firefox ESR | All versions |
CPE
Remediation
| |
| Mozilla Thunderbird | All versions |
CPE
Remediation
| |
Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Oct 30, 2026 | CVE Modified | CISA-ADP |
| Oct 13, 2026 | CVE Modified | [email protected] |
| Oct 13, 2026 | New CVE Received | [email protected] |