Medium (6.1). EPSS 0.6% chance of exploitation in the next 30 days.
If two same-origin documents set document.domain differently to become cross-origin, it was possible for them to call arbitrary DOM methods/getters/setters on the now-cross-origin window. This vulnerability affects Firefox < 70, Thunderbird < 68.2, and Firefox ESR < 68.2.
Severity
CVSS 3.1
6.1 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS
0.6% chance of exploitation in the next 30 days; higher than 49% of CVEs (scores of 2026-10-31)