Service crash via trailing-whitespace parser underflow
Published Jan 28, 2026 · Updated Jan 28, 2026
Out-of-bounds write in YATinyWinFTP 0.0.5 allows remote attackers to crash the FTP service with a space-terminated command. The request parser’s trailing-whitespace loop applies its bounds check only to the space test, so CR/LF tests continue dereferencing and decrementing the end pointer beyond the input buffer. Any unauthenticated network client that can reach the configured FTP port can interrupt the service process with one malformed command.
Summary
What happened
Out-of-bounds write in YATinyWinFTP 0.0.5 allows remote attackers to crash the FTP service with a space-terminated command. The request parser’s trailing-whitespace loop applies its bounds check only to the space test, so CR/LF tests continue dereferencing and decrementing the end pointer beyond the input buffer. Any unauthenticated network client that can reach the configured FTP port can interrupt the service process with one malformed command.
The record
- CVE
- CVE-2020-36964
- Published
- Jan 28, 2026
- Updated
- Jan 28, 2026
- Vendor
- ik80
- Product
- YATinyWinFTP
- Classifications
- CWE-787, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 28, 2026CVE publishedPublication date reported by the CVE source.
- Jan 28, 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=0.0.5
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
- YATinyWinFTP - Denial of Service (PoC)proof of concept · unverified
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Technologies
Your stack
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Your stack
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