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.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 2
- StatusReceived → Awaiting AnalysisNVD modified 2026-10-16 16:00
- First seenCVSS 5.3NVD modified 2026-10-13 18:17
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 4
- https://github.com/duty1g/x64dbg-mcp-server/commit/0dd4204d37c81d8b605133dc48c14886eeac1562
- https://github.com/duty1g/x64dbg-mcp-server/releases/tag/v1.2
- https://github.com/duty1g/x64dbg-mcp-server/security/advisories/GHSA-4478-h5jv-647m
- https://github.com/duty1g/x64dbg-mcp-server/security/advisories/GHSA-jgj3-97w2-9v9r