High (7.5). EPSS 4.6% chance of exploitation in the next 30 days.
The System Only Wrapper (SOW) implementation in Mozilla Firefox before 27.0, Firefox ESR 24.x before 24.3, Thunderbird before 24.3, and SeaMonkey before 2.24 does not prevent certain cloning operations, which allows remote attackers to bypass intended restrictions on XUL content via vectors involving XBL content scopes.
Severity
CVSS 3.1
7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS
4.6% chance of exploitation in the next 30 days; higher than 91% of CVEs (scores of 2026-10-31)