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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-107820
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-09 18:17:03 UTC
Updated2026-10-09 18:17:03 UTC
Descriptionx64dbg-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.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

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

Problem Types: CWE-190 | CWE-190 CWE-190: Integer Overflow or Wraparound

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
3.1CNADECLARED5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Duty1g X64dbg-mcp-server affected < 1.2 Not specified

References

ReferenceSourceLinkTags
github.com/duty1g/x64dbg-mcp-server/security/advisories/GHSA-4478-h5jv-647m [email protected] github.com
github.com/duty1g/x64dbg-mcp-server/releases/tag/v1.2 [email protected] github.com
github.com/duty1g/x64dbg-mcp-server/commit/0dd4204d37c81d8b605133dc48c14... [email protected] github.com
github.com/duty1g/x64dbg-mcp-server/security/advisories/GHSA-jgj3-97w2-9v9r [email protected] github.com
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