← WebKit Silent-Fix Report — 2026-W23

fec133e2eaadbecd135945e4090f561497e055af  [Site Isolation] Cross-origin popup navigating to about:blank crashes

severity medium class LogicError confidence 0.55 WebKit Site Isolation
Roberto Rodriguez Tue Jun 2 06:43:29 2026 -0700 full: fec133e2eaadbecd135945e4090f561497e055af bug report ↗ view on GitHub ↗
Primitive: Cross-origin popup navigating to about:blank crashes under site isolation
Triage note: ProvisionalPageProxy::initializeWebPage mishandled main-frame reuse and commit timing for about:blank in a cross-origin popup; fix always passes the main frame id and uses CommitTiming::Immediately for about:blank, removing the expected crash from TestExpectations, a site-isolation navigation crash.

Security-relevant, below the exploitable-grade bar for a full root-cause writeup. The triage verdict is above; the side-by-side patch is below.

Before / after

Loading diff…