Array element overwrite via zero-count JIT slice
Published Dec 22, 2022 · Updated Apr 15, 2025
Out-of-bounds write in Firefox before 104 allows remote attackers to alter the first element of a zero-length JavaScript array. The JIT CodeGenerator's inline arguments-slice path assumes that a nonzero argument list yields a nonzero slice count and stores at NativeObject::elements[0]. Execution requires a user to load attacker-controlled JavaScript; Mozilla states that the destination remains allocated, so no invalid-memory write occurs.
Summary
What happened
Out-of-bounds write in Firefox before 104 allows remote attackers to alter the first element of a zero-length JavaScript array. The JIT CodeGenerator's inline arguments-slice path assumes that a nonzero argument list yields a nonzero slice count and stores at NativeObject::elements[0]. Execution requires a user to load attacker-controlled JavaScript; Mozilla states that the destination remains allocated, so no invalid-memory write occurs.
The record
- CVE
- CVE-2022-38475
- Published
- Dec 22, 2022
- Updated
- Apr 15, 2025
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- CWE-863
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 22, 2022CVE publishedPublication date reported by the CVE source.
- Apr 15, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified <104
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
- Bug 1773266 JavaScript testcaseproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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