Vulnerability · Published Oct 30, 2026 · Assigned by GitHub_M
CVE-2026-119332Ladybird: FinalizationRegistry::cleanup() heap use-after-free via reentrant unregister()
High 8.8
In plain English
A high-severity use-after-free in ladybird from LadybirdBrowser. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities).
Official description
Ladybird is a truly independent web browser. Prior to 209579c96473c75bd5eba9701fcadb841a045964, FinalizationRegistry::cleanup() in Libraries/LibJS/Runtime/FinalizationRegistry.cpp removed a dead record from m_records, retained an iterator to the next FinalizationRecord, and then invoked attacker-controlled JavaScript through the cleanup callback. If that callback called unregister() for the next record, remove_by_token() freed the node referenced by the retained iterator, and the next cleanup iteration read its target and held_value fields after free. This reliably crashes instrumented WebContent builds and creates a memory-corruption primitive in production builds. This vulnerability is fixed by commit 209579c96473c75bd5eba9701fcadb841a045964.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| LadybirdBrowser | ladybird | < 209579c96473c75bd5eba9701fcadb841a045964 |
Weakness: CWE-416 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H