Ladybird - Web-Reachable Code Execution via Dangling FunctionType Reference in WebAssembly ESM Integration
Summary
| CVE | CVE-2026-58592 |
|---|---|
| State | PUBLISHED |
| Assigner | VulnCheck |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-01 20:17:11 UTC |
| Updated | 2026-07-02 17:42:23 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v4.0 8.9 HIGH from [email protected]
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Problem Types: CWE-787 | CWE-825 | CWE-843 | CWE-825 Expired Pointer Dereference | CWE-843 Access of Resource Using Incompatible Type (Type Confusion) | CWE-787 Out-of-bounds Write
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 8.9 | HIGH | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/C... |
| 4.0 | CNA | CVSS | 8.9 | HIGH | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H |
| 3.1 | [email protected] | Secondary | 8.3 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H |
| 3.1 | CNA | CVSS | 8.3 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
HighAttack Requirements
PresentPrivileges Required
NoneUser Interaction
ActiveConfidentiality
HighIntegrity
HighAvailability
HighSub Conf.
HighSub Integrity
HighSub Availability
HighCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
RequiredScope
ChangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | LadybirdBrowser | Ladybird | affected | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.vulncheck.com/advisories/ladybird-web-reachable-code-execution-via-dangling... | [email protected] | www.vulncheck.com | |
| github.com/LadybirdBrowser/ladybird/blob/master/Libraries/LibWeb/WebAsse... | [email protected] | github.com | |
| github.com/bikini/exploitarium/tree/main/ladybird-wasm-esm-host-function... | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.