← WebKit Silent-Fix Report — 2026-W25

1d2be470ed  [JSC] Make poisonedDeadOSRExitValue more crashy and enable this option when build is Debug

severity dev class Other confidence 0.45 JSC DFG/FTL OSR exit
Yusuke Suzuki Fri Jun 19 09:32:23 2026 -0700 full: 1d2be470eda916d00dda8f21cbf531b43eb80c87 bug report ↗ view on GitHub ↗
Primitive: hardening to crash on dead-variable reads
Triage note: Diagnostic hardening that surfaces DFG/FTL OSR liveness bugs (which are exploitable) at the access site; itself a debug-only mitigation.

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…