Heap-buffer-overflow in /src/wasm/wasm-binary.cpp in wasm::WasmBinaryBuilder::visitBlock(wasm::Block*) in Binaryen 1.38.26. A crafted wasm input can cause a segmentation fault, leading to denial-of-service, as demonstrated by wasm-opt.

A NULL pointer dereference was discovered in SExpressionWasmBuilder::makeBlock in wasm/wasm-s-parser.c in Binaryen 1.38.26. A crafted wasm input can cause a segmentation fault, leading to denial-of-service, as demonstrated by wasm-as.