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Out-of-bounds WriteWeakness · CWE-787

CVE-2020-36964

CRITICAL · 9.8 CVSS v3.1 Published 2026-01-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
YATinyWinFTP contains a denial of service vulnerability that allows attackers to crash the FTP service by sending a 272-byte buffer with a trailing space. Attackers can exploit the service by connecting and sending a malformed command that triggers a buffer overflow and service crash.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

YATinyWinFTP contains a buffer overflow vulnerability that allows remote attackers to crash the FTP service by sending a 272-byte buffer with a trailing space as a malformed command. The overflow triggers during command processing, causing a denial of service condition.

MitigationIf a vendor patch is available, apply it immediately. Otherwise, implement network-level access controls to restrict FTP access to trusted sources only, or consider migrating to a maintained FTP server solution.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if YATinyWinFTP is installed
    Search for YATinyWinFTP in installed programs (Windows: Add/Remove Programs, Linux: package manager or find the executable)
    Affected if The software is present on the system
  2. Identify the installed version
    Check the executable properties, help menu, or any version file that came with the installation
    Affected if The version matches or precedes the affected version range for this CVE
  3. Verify the FTP service is running
    Check if the YATinyWinFTP service is active and listening on port 21 (netstat -an | findstr :21 or similar)
    Affected if The FTP service is exposed and accessible
  4. Review FTP access logs for malformed 272-byte commands
    Examine FTP server logs for entries containing unusually long commands around 272 bytes, especially those with trailing spaces
    Affected if Such malformed commands appear in the logs indicating exploitation attempts

You are affected if YATinyWinFTP is running and the identified version falls within the vulnerable version range for CVE-2020-36964.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

If a vendor patch is available, apply it immediately. Otherwise, implement network-level access controls to restrict FTP access to trusted sources only, or consider migrating to a maintained FTP server solution.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-36964 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data