CVE-2025-66902
Published: 20 January 2026
Summary
CVE-2025-66902 is a high-severity Improper Input Validation (CWE-20) vulnerability in Pithikos Websocket Server. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 26.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2025-66902 is an input validation vulnerability (CWE-20) in Pithikos websocket-server version 0.6.4. The flaw affects the websocket_server/websocket_server.py file, specifically the WebSocketServer._message_received component, enabling a remote attacker to obtain sensitive information or cause unexpected server behavior.
The vulnerability has a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N), indicating it is exploitable remotely over the network with low attack complexity, no required privileges, and no user interaction. Any unauthenticated attacker who can connect to the WebSocket server can send crafted messages to disclose sensitive data or disrupt normal server operations.
A proof-of-concept demonstrating the vulnerability is available at https://github.com/cyberinvest211/websocket-server-vuln-poc/tree/main. No vendor advisories, patches, or specific mitigation guidance are detailed in the provided references.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-3328
Vulnerability details
An input validation issue in in Pithikos websocket-server v.0.6.4 allows a remote attacker to obtain sensitive information or cause unexpected server behavior via the websocket_server/websocket_server.py, WebSocketServer._message_received components.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct remote exploitation of a public-facing WebSocket server via crafted input for sensitive data disclosure.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mandates validation of WebSocket message inputs to prevent crafted messages from disclosing sensitive information or causing unexpected behavior.
Requires timely flaw remediation, such as patching the input validation issue in Pithikos websocket-server v0.6.4's _message_received component.
Ensures secure error handling to mitigate information disclosure and limit unexpected server behavior resulting from invalid WebSocket inputs.