CVE-2026-30618: xszyou Fay 4.3.1 contains a remote code execution vulnerability in its MCP STDIO server management and command

This month

CRITICAL 9.8REMOTE

CVE-2026-30618 is a critical-severity flaw (CVSS 9.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 32%)
CISA exploited list	No
Weakness	CWE-94
Published	2026-07-15
Last modified	2026-07-16

Publisher (CNA): MITRE

Last updated 2026-07-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-07-15 22:16 UTCPublished CVE record published
2026-07-16 14:16 UTCUpdated Record last modified

Exact fixes by distribution

Fedora 46 · gcl · FIXED · 2.7.1-12.fc46 · FEDORA-2026-ff383a759b · source

sudo dnf upgrade --advisory=FEDORA-2026-ff383a759b

Fedora ELN · mozjs140 · FIXED · 140.13.0-5.eln159 · FEDORA-2026-f7ed0026e0 · source

sudo dnf upgrade --advisory=FEDORA-2026-f7ed0026e0

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-30618?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-30618 being exploited?

CVE-2026-30618 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-30618 affect?

CVE-2026-30618 affects affected software. Severity is critical (CVSS 9.8). 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

How urgent is CVE-2026-30618?

Priority 59/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

References

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