CVE-2026-58592

What it is

Ladybird before commit 2f9dc7e 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.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, data tampering, service disruption.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-07-01 20:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-25 16:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.5% in the next 30 days (EPSS).
• Severity: 8.9 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-07-01 20:17 UTC

Last modified

2026-10-25 16:10 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-787 · Out-of-bounds write

Record status

Deferred

Attack profile CVSS 4.0 · 8.9

Attack vector

Network

Complexity

High

Attack requirements

Present

Privileges needed

None

User interaction

Active

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-58592.md and follow it. Check whether this project is affected by CVE-2026-58592. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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