App crash and truncation via UTF-8 undercount
Published Jun 23, 2026 · Updated Jun 23, 2026
Buffer corruption in Electron 42.3.1 through 42.3.2 allows attackers to crash apps or truncate encoded data via crafted text. On Apple Silicon, an LLVM loop-unrolling miscompilation makes simdutf's utf8_length_from_latin1 undercount some Latin-1 strings, so Buffer and TextEncoder allocate or emit too few bytes. Exposure requires an affected Apple Silicon macOS or Mac App Store build to process attacker-controlled text with the affected Node.js APIs; Linux and Windows builds cannot trigger this compiler defect.
Summary
What happened
Buffer corruption in Electron 42.3.1 through 42.3.2 allows attackers to crash apps or truncate encoded data via crafted text. On Apple Silicon, an LLVM loop-unrolling miscompilation makes simdutf's utf8_length_from_latin1 undercount some Latin-1 strings, so Buffer and TextEncoder allocate or emit too few bytes. Exposure requires an affected Apple Silicon macOS or Mac App Store build to process attacker-controlled text with the affected Node.js APIs; Linux and Windows builds cannot trigger this compiler defect.
The record
- CVE
- CVE-2026-54257
- Published
- Jun 23, 2026
- Updated
- Jun 23, 2026
- Vendor
- Electron
- Product
- Electron
- Classifications
- CWE-120, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 23, 2026CVE publishedPublication date reported by the CVE source.
- Jun 23, 2026Record 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=>= 42.3.1, < 42.3.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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
- Buffer.byteLength and Buffer.from macOS reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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