Code execution via accessor-triggered HiddenClass mutation
Published May 18, 2023 · Updated Jan 21, 2025
Type confusion in Meta Platforms Hermes before commit a00d237 allows attackers to execute arbitrary code through untrusted JavaScript. The hermesBuiltinCopyDataProperties fast path invokes getters during JSObject::forEachOwnPropertyWhile iteration, allowing a getter to mutate the source object's HiddenClass contrary to the iterator precondition. Exploitation requires an embedding that executes attacker-controlled JavaScript; most React Native applications do not expose that condition.
Summary
What happened
Type confusion in Meta Platforms Hermes before commit a00d237 allows attackers to execute arbitrary code through untrusted JavaScript. The hermesBuiltinCopyDataProperties fast path invokes getters during JSObject::forEachOwnPropertyWhile iteration, allowing a getter to mutate the source object's HiddenClass contrary to the iterator precondition. Exploitation requires an embedding that executes attacker-controlled JavaScript; most React Native applications do not expose that condition.
The record
- CVE
- CVE-2023-23557
- Published
- May 18, 2023
- Updated
- Jan 21, 2025
- Vendor
- Meta Platforms, Inc.
- Product
- Hermes
- Classifications
- CWE-843
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 18, 2023CVE publishedPublication date reported by the CVE source.
- Jan 21, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <a00d237346894c6067a594983be6634f4168c9ad
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Your stack
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Your stack
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