{"id":"CVE-2026-58592","summary":"Ladybird - Web-Reachable Code Execution via Dangling FunctionType Reference in WebAssembly ESM Integration","details":"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.","modified":"2026-09-15T08:16:11.026021Z","published":"2026-07-01T19:27:22.629Z","database_specific":{"unresolved_ranges":[{"extracted_events":[{"fixed":"2f9dc7e9f35eed67dde3f9e8567d390dc4f0c665"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"VulnCheck","cwe_ids":["CWE-787","CWE-825","CWE-843"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58592.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58592.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58592"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/ladybird-web-reachable-code-execution-via-dangling-functiontype-reference-in-webassembly-esm-integration"},{"type":"REPORT","url":"https://github.com/LadybirdBrowser/ladybird/issues/11569"},{"type":"REPORT","url":"https://github.com/LadybirdBrowser/ladybird/pull/11606"},{"type":"FIX","url":"https://github.com/LadybirdBrowser/ladybird/commit/2f9dc7e9f35eed67dde3f9e8567d390dc4f0c665"},{"type":"EVIDENCE","url":"https://github.com/bikini/exploitarium/tree/main/ladybird-wasm-esm-host-function-rce-poc"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/ladybirdbrowser/ladybird","events":[{"introduced":"0"},{"fixed":"2f9dc7e9f35eed67dde3f9e8567d390dc4f0c665"}],"database_specific":{"source":"REFERENCES"}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-58592.json","vanir_signatures_modified":"2026-09-15T08:16:11Z","vanir_signatures":[{"deprecated":false,"digest":{"function_hash":"278077153142881579293324696797394102485","length":1954},"id":"CVE-2026-58592-06ac5ee4","signature_type":"Function","signature_version":"v1","source":"https://github.com/ladybirdbrowser/ladybird/commit/2f9dc7e9f35eed67dde3f9e8567d390dc4f0c665","target":{"file":"Libraries/LibWeb/WebAssembly/WebAssembly.cpp","function":"create_host_function"}},{"id":"CVE-2026-58592-b7f9a931","signature_type":"Line","signature_version":"v1","source":"https://github.com/ladybirdbrowser/ladybird/commit/2f9dc7e9f35eed67dde3f9e8567d390dc4f0c665","target":{"file":"Libraries/LibWeb/WebAssembly/WebAssembly.cpp"},"deprecated":false,"digest":{"line_hashes":["50025981111056851015323799720141825841","212876726051289525556503390840039359360","76354069761241732907327441952815569935","184640994911411297426766025871710553633"],"threshold":0.9}}]}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}