System termination via SMB out-of-bounds read
Published Sep 14, 2026 · Updated Sep 14, 2026
An out-of-bounds read in Apple macOS SMB allows remote attackers controlling an SMB server to terminate the connecting system. The SMB client performs insufficient bounds checking and reads past a buffer while processing data from the malicious server; Apple has not disclosed the affected function or message field. Exploitation requires the Mac to connect to an attacker-controlled SMB server, and the documented consequence is a system crash without reported data disclosure or code execution.
Summary
What happened
An out-of-bounds read in Apple macOS SMB allows remote attackers controlling an SMB server to terminate the connecting system. The SMB client performs insufficient bounds checking and reads past a buffer while processing data from the malicious server; Apple has not disclosed the affected function or message field. Exploitation requires the Mac to connect to an attacker-controlled SMB server, and the documented consequence is a system crash without reported data disclosure or code execution.
The record
- CVE
- CVE-2026-84509
- Published
- Sep 14, 2026
- Updated
- Sep 14, 2026
- Vendor
- Apple
- Product
- macOS
- Classifications
- T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 14, 2026CVE publishedPublication date reported by the CVE source.
- Sep 14, 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=0 <15.8
- Affected versionversion=0 <26.7
- Affected versionversion=0 <27
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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