Bug 2568417 (CVE-2026-119332)

Summary: CVE-2026-119332 ladybird: ladybird: Arbitrary code execution via use-after-free during FinalizationRegistry cleanup
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerability-draftAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: high    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in Ladybird. A remote attacker could achieve arbitrary code execution or cause a Denial of Service (DoS) by enticing a user to visit a malicious website running specially crafted JavaScript. During registry cleanup in the JavaScript engine, executing a callback that unregisters subsequent records triggers a use-after-free condition where memory is accessed after being freed.
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Description OSIDB Bzimport 2026-11-06 18:21:27 UTC 
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.