CVE-2026-58592
Published:July 01, 2026
Updated:July 21, 2026
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.
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Contact UsCVSS v4
Base Score:
8.9
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
ACTIVE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
HIGH
Subsequent System Integrity
HIGH
Subsequent System Availability
HIGH
CVSS v3
Base Score:
8.3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
EPSS
Base Score:
0.31