Pre-auth memory corruption via SSH GCM overflow
Published Jul 29, 2026 · Updated Jul 29, 2026
Stack buffer overflow in Xlight FTP Server before 3.9.5 allows remote attackers to corrupt memory via malformed SSH GCM packets. The SSH packet handler passes an attacker-controlled length directly to the GCM decrypt function, allowing writes beyond a stack buffer. An SFTP endpoint must negotiate a GCM cipher, but no authentication or user interaction is required; stack-cookie and return-address corruption creates a path to code execution in the server process.
Summary
What happened
Stack buffer overflow in Xlight FTP Server before 3.9.5 allows remote attackers to corrupt memory via malformed SSH GCM packets. The SSH packet handler passes an attacker-controlled length directly to the GCM decrypt function, allowing writes beyond a stack buffer. An SFTP endpoint must negotiate a GCM cipher, but no authentication or user interaction is required; stack-cookie and return-address corruption creates a path to code execution in the server process.
The record
- CVE
- CVE-2026-67192
- Published
- Jul 29, 2026
- Updated
- Jul 29, 2026
- Vendor
- Xlight
- Product
- Xlight FTP Server
- Classifications
- T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 29, 2026CVE publishedPublication date reported by the CVE source.
- Jul 29, 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 <3.9.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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