← WebKit Silent-Fix Report — 2026-W23

bf80e3eedd686c0fe2ecce39b3143e6279a89103  [grid layout] Don't call viewportContentsChanged() from scroll updates during render tree layout

severity medium class LogicError confidence 0.55 WebCore Rendering
Zak Ridouh Fri Jun 5 02:59:10 2026 -0700 full: bf80e3eedd686c0fe2ecce39b3143e6279a89103 bug report ↗ view on GitHub ↗
Primitive: Reentrant viewportContentsChanged() from scroll during grid render-tree layout
Triage note: RenderLayerScrollableArea::scrollTo called frameView().viewportContentsChanged() while inside render-tree layout, causing a reentrant-layout crash (grid + vertical-rl overflow + transformed child); fix guards the call with !layoutContext().isInRenderTreeLayout().

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

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