CVE intelligence and bounded remediation

CVE-2026-58592 — Ladybird contains a dangling-reference memory-safety flaw in its WebAssembly ESM-integration module loader

Ladybird contains a dangling-reference memory-safety flaw in its WebAssembly ESM-integration module loader. When a JavaScript function is imported into a WebAssembly module via the ESM path, WebAssemblyModule.cpp passes a stack-local Wasm::FunctionType by reference to create_host_function, whose host callback captures and later reads that reference; once the ESM link-loop iteration ends the FunctionType is destroyed, leaving the callback with a dangling reference (the normal instantiate path uses a long-lived reference and is not affected). Stale result-type data lets the host callback return an empty result vector for a statically non-empty result, so the destination register retains an attacker-influenced value that is then consumed by the WASM-GC array.set handler, which bit-casts the reference low bits to an ArrayInstance pointer after only a null check, yielding an arbitrary write. A web page can chain this into code execution in the WebContent process. Verified reachable from HTML content without any instrumentation or source modification.

Severity

High

CVSS

8.9 (4.0)

Published

2026-07-01

CISA KEV

Not currently listed

Ecosystem

javascript/npm

Weaknesses

CWE-787, CWE-825, CWE-843