WebKit/Source/core/css/StyleSheetContents.cpp in Blink, as used in Google Chrome before 51.0.2704.63, permits cross-origin loading of CSS stylesheets by a ServiceWorker even when the stylesheet download has an incorrect MIME type, which allows remote attackers to bypass the Same Origin Policy via a crafted web site.
Severity
CVSS 3.0
5.3 medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS
1.1% chance of exploitation in the next 30 days; higher than 66% of CVEs (scores of 2026-10-31)