All vulnerabilities
CVE-2026-107820GHSA-4478-h5jv-647mGHSA-jgj3-97w2-9v9r

x64dbg-mcp-server: x64dbg-MCP Server vulnerable to pre-authentication denial of service through Content-Length integer overflow

duty1g x64dbg-mcp-server
CVSS
5.3Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.41%Chance of exploitation activity in the next 30 days, higher than 34% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in1.2Fixed versionGitHub
Published9 Oct 2026Updated 13 Oct 2026CVE List

What fixes it

  • 1.2x64dbg-mcp-server, otherGitHub

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

x64dbg-MCP Server is a native Model Context Protocol (MCP) plugin for x64dbg that exposes the debugger's full functionality over HTTP. Prior to 1.2, src/core/mcp_server.zig parses an unbounded Content-Length value in parseContentLength() and uses it in unchecked usize addition in wsRecv() before token authentication. The server listens on 0.0.0.0 by default in affected versions. An unauthenticated network client can supply a near-maximum Content-Length value to trigger a runtime integer-overflow panic in Debug and ReleaseSafe builds, terminating the entire x64dbg process and its live debugging session. The overflowed value is used only in a comparison, so the impact is limited to denial of service rather than memory corruption or code execution. This issue is fixed in version 1.2.

Text from CVE List

Affected versions 2

  • x64dbg-mcp-serveraffected: < 1.2CVE List
  • x64dbg-mcp-server, other<= 1.1GitHub

References 4