asworkjsc
JSC security specialist
Summary
Works almost entirely in JavaScriptCore, with the bulk of the work in the WebAssembly stack — IPInt interpreter bounds/metadata handling, BBQ constant folding, WasmGC decoding, streaming compilation, and the multimemory and relaxed SIMD feature flags — alongside scattered Yarr JIT, B3, DFG, and Temporal changes. The security fixes track the same surface they build: shipping multimemory support and then fixing an IPInt bounds-check underflow on zero-size memories, plus reserved-bit validation in `br_on_cast` flags and a streaming-compiler gap that accepted mixed legacy and spec-correct exception handling. Systematic-variant candidate: the wasm decoder's handling of reserved/undefined bits and validation paths that differ between streaming and one-shot compilation, where the same class of gap has already surfaced more than once.
Components
Security Fix History
- 2026-07-01 Change IPInt m_pendingOffset to std::optional and add metadata offset overflow assertions ·
- 2026-07-01 WasmGC should reject reserved bits in br_on_cast/br_on_cast_fail flags byte ·
- 2026-07-01 Streaming compiler does not reject mixed legacy and spec-correct EH ·
- 2026-06-30 Add size limit to Yarr generated code ·
- 2026-06-30 YarrJIT negativeOffsetIndexedAddress discards adjusted base register ·
- 2026-06-02 Fix baseline write barrier handling in OpDelBy{Id,Val} 2026-W22
- 2026-05-26 Fix dominance analysis in B3CanonicalizePrePostIncrements
- 2026-05-24 WebAssemblyCompileOptions::tryCreate should throw on OOM
- 2026-03-05 operationNewRegExpUntyped should call constructRegExp with a newTarget 2026-W09
Hardening Commits
- No hardening commits recorded
Recent Commits
- 2026-08-04 Widen JS Temporal time zone cache in TimeZoneICUBridge.cpp
- 2026-07-23 Mark crash-on-overflow functions in WTF OverflowHandler.h as NODELETE
- 2026-07-22 Clean up JS Temporal getNamedTimeZoneEpochNanoseconds
- 2026-07-21 Enable wasm multimemory feature flag
- 2026-07-20 Enable wasm relaxed SIMD feature flag
- 2026-07-01 Change IPInt m_pendingOffset to std::optional and add metadata offset overflow assertions ·
- 2026-07-01 WasmGC should reject reserved bits in br_on_cast/br_on_cast_fail flags byte ·
- 2026-07-01 Streaming compiler does not reject mixed legacy and spec-correct EH ·
- 2026-06-30 Add size limit to Yarr generated code ·
- 2026-06-30 YarrJIT negativeOffsetIndexedAddress discards adjusted base register ·
- 2026-06-24 Check if JSArray::fastFlat exceeds maximum legal length
- 2026-06-02 Fix baseline write barrier handling in OpDelBy{Id,Val} 2026-W22
- 2026-05-29 Add myself as a committer
- 2026-05-26 Fix dominance analysis in B3CanonicalizePrePostIncrements
- 2026-05-24 WebAssemblyCompileOptions::tryCreate should throw on OOM