CVE-2026-30618: Code Injection (CVSS 9.8)

Description

xszyou Fay 4.3.1 contains a remote code execution vulnerability in its MCP STDIO server management and command execution handling. A remote attacker can access the publicly exposed MCP management interface and configure an MCP STDIO server with attacker-controlled commands and parameters, resulting in execution of arbitrary commands on the server. Successful exploitation allows arbitrary command execution within the context of the Fay service.

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CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0167

Probability of exploitation

0.74%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-94 CWE-94

References

Other References

https://github.com/xszyou/Fay https://www.ox.security/blog/mcp-supply-chain-advisory-rce-vulnerabilities-across-the-ai-ecosystem/

Frequently Asked Questions

What is CVE-2026-30618? +

xszyou Fay 4.3.1 contains a remote code execution vulnerability in its MCP STDIO server management and command execution handling. A remote attacker can access the publicly exposed MCP management interface and configure an MCP STDIO server with attacker-controlled commands and parameters, resulting in execution of arbitrary commands on the server. Successful exploitation allows arbitrary command execution within the context of the Fay service. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-30618? +

CVE-2026-30618 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0167, placing it in the 1th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-30618? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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