ThinvncApplication · Cybelsoft

CVE-2022-25226

CRITICAL · 10.0 CVSS v3.1 Published 2022-04-18
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
ThinVNC version 1.0b1 allows an unauthenticated user to bypass the authentication process via 'http://thin-vnc:8080/cmd?cmd=connect' by obtaining a valid SID without any kind of authentication. It is possible to achieve code execution on the server by sending keyboard or mouse events to the server.

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 · high confidence

ThinVNC 1.0b1 contains an authentication bypass vulnerability where unauthenticated users can obtain a valid session ID (SID) by accessing the '/cmd?cmd=connect' endpoint, completely bypassing the login mechanism. Once authenticated by proxy, an attacker can send keyboard and mouse events to achieve remote code execution on the server.

MitigationImmediately restrict network access to ThinVNC to trusted IPs only, or if possible, upgrade to a patched version. Consider deploying a reverse proxy with strong authentication in front of ThinVNC or migrating to a supported VNC solution with proper authentication.

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

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
ThinvncApplication
Affected:= 1.0

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
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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. Confirm ThinVNC is installed and running
    Check for processes named ThinVNC.exe or services listening on VNC default ports (typically 5900, 5901 or HTTP port 80/8080). Use commands like 'tasklist | findstr ThinVNC' or 'netstat -an | grep -E "590[0-9]|80|8080"'
    Affected if ThinVNC process is found running on the system
  2. Verify the ThinVNC version
    Check the installed version against the affected range. For ThinVNC, the version is typically displayed in the application title bar, in the executable's properties, or in the installation directory's version info. Compare to the affected version: 1.0
    Affected if The installed version is exactly 1.0 (or 1.0b1)
  3. Test for the vulnerable endpoint accessibility
    If ThinVNC has a web interface, attempt to access the '/cmd?cmd=connect' endpoint via HTTP (e.g., http://<server>/cmd?cmd=connect). A valid response indicates the vulnerable endpoint is exposed
    Affected if The '/cmd?cmd=connect' endpoint responds without requiring authentication
  4. Check network exposure
    Review firewall rules and network access controls to determine if ThinVNC web interface (port 80/8080 or configured HTTP port) is accessible from untrusted networks. Use 'netsh advfirewall firewall show rule name=all' or review inbound firewall rules
    Affected if ThinVNC HTTP interface is accessible from untrusted/external IP addresses or the internet

You are affected if ThinVNC version 1.0 is running and the '/cmd?cmd=connect' endpoint is accessible without authentication from an untrusted network.

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

Immediately restrict network access to ThinVNC to trusted IPs only, or if possible, upgrade to a patched version. Consider deploying a reverse proxy with strong authentication in front of ThinVNC or migrating to a supported VNC solution with proper authentication.

Fix this in Thinvnc Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2022-25226 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