CVE-2026-109778

Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

CVSS v3 8.8 HIGH

8.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=2070547
https://www.mozilla.org/security/advisories/mfsa2026-106/
https://www.mozilla.org/security/advisories/mfsa2026-108/
https://www.mozilla.org/security/advisories/mfsa2026-109/
https://www.mozilla.org/security/advisories/mfsa2026-110/

Configurations

No configuration.

History

13 Oct 2026, 19:18

Type	Values Removed	Values Added
Summary	~~(en) Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.~~	(en) Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
References		() https://www.mozilla.org/security/advisories/mfsa2026-109/ - () https://www.mozilla.org/security/advisories/mfsa2026-110/ -

13 Oct 2026, 15:17

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 8.8
CWE		CWE-269

13 Oct 2026, 13:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-13 13:17

Updated : 2026-10-14 04:18

NVD link : CVE-2026-109778

Mitre link : CVE-2026-109778

CVE.ORG link : CVE-2026-109778

JSON object : View

Products Affected

No product.

CWE

CWE-269

Improper Privilege Management

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