CVE-2022-25226: 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…

PriorityP182critical10CVSS 3.1

AVNACLPRNUINSCCHIHAH

EXPLOIT

EPSS

10.87%

95.3th percentile

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.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
cybelsoft	thinvnc	—	—
cybelsoft	thinvnc	—	—

Detection & IOCsextracted from sources · hover to see the quote

urlhttp://thin-vnc:8080/cmd?cmd=connect↗

url{{BaseURL}}/cmd?cmd=connect

otherhttp.favicon.hash:-1414548363

othericon_hash="571240285"

→HTTP GET request to /cmd?cmd=connect endpoint on ThinVNC server returns a 200 response containing both 'cmd":"connectStatus' and 'authStatus":1' in the body, indicating successful authentication bypass without credentials.
→Identify exposed ThinVNC 1.0b1 instances via Shodan using favicon hash -1414548363 or FOFA using icon_hash 571240285.
→Authentication bypass allows unauthenticated SID acquisition; subsequent keyboard/mouse event messages to the server can achieve code execution. ↗

·ThinVNC default port is 8080; detection should target this port unless the deployment uses a non-standard port. ↗
·The vulnerability is confirmed only for ThinVNC version 1.0b1 (CPE: cpe:2.3:a:cybelsoft:thinvnc:1.0:b1); other versions may not be affected.

CVSS provenance

nvdv3.110.0CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P

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