CVE-2026-119332

Ladybird: FinalizationRegistry::cleanup() heap use-after-free via reentrant unregister()

HIGH
8.8
CVSS Score
Published: October 30, 2026 at 07:57 PM UTC
Updated: October 30, 2026 at 08:17 PM UTC
1 product affected across 1 vendorLadybird

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Severity
HIGH8.8
Exploit prediction
EPSS 0.2%

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

< 209579c96473c75bd5eba9701fcadb841a045964

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

8.8HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusRECEIVED
CWE
CWE-416

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