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.
History

Sat, 07 Nov 2026 07:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Fri, 30 Oct 2026 23:00:00 +0000

Type Values Removed Values Added
First Time appeared Ladybirdbrowser
Ladybirdbrowser ladybird
Vendors & Products Ladybirdbrowser
Ladybirdbrowser ladybird

Fri, 30 Oct 2026 20:15:00 +0000

Type Values Removed Values Added
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.
Title Ladybird: FinalizationRegistry::cleanup() heap use-after-free via reentrant unregister()
Weaknesses CWE-416
References
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-10-30T19:57:47.291Z

Updated: 2026-11-06T18:00:51.305Z

Reserved: 2026-10-29T20:44:30.285Z

Link: CVE-2026-119332

cve-icon Vulnrichment

Updated: 2026-11-06T18:00:05.813Z

cve-icon NVD

Status : Deferred

Published: 2026-10-30T20:17:07.600

Modified: 2026-11-06T19:17:38.840

Link: CVE-2026-119332

cve-icon Redhat

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