The CSPSource::schemeMatches function in WebKit/Source/core/frame/csp/CSPSource.cpp in the Content Security Policy (CSP) implementation in Blink, as used in Google Chrome before 48.0.2564.82, does not apply http policies to https URLs and does not apply ws policies to wss URLs, which makes it easier for remote attackers to determine whether a specific HSTS web site has been visited by reading a CSP report.