CVE-2026-28907: align ContentSecurityPolicySource::pathMatches() with the CSP3
path-matching algorithm to prevent path-traversal CSP bypass (WebKit bug 308675)
CVE-2026-43660: preserve all CSP policies when a blob: URL inherits from a page
that sent multiple CSP headers (WebKit bug 308906)
CVE-2026-28958: pass the initiator when computing SameSite info in
FrameLoader::load to prevent SameSite=Strict cookie cross-site leakage (WebKit bug 311228)