CVE-2026-107820
MEDIUM 5.3x64dbg-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.
No known exploitation, public exploit, or elevated probability at this time. Track for changes.
Exploitation likelihood
0.4%chance of exploitation in 30 days · 35th percentile
Impact if exploited
5.3CVSS 3.1 · MEDIUM
- ConfidentialityNone
- IntegrityNone
- AvailabilityLow
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
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Data snapshot:
Weakness (CWE)
- CWE-190: : Integer Overflow or Wraparound
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References and research data (JSON)
All CVSS metrics
- MEDIUM 5.3 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - MEDIUM 5.3 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References
Advisories
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-95928 EUVD · EUVD-2026-95928
Technical & other
- https://github.com/duty1g/x64dbg-mcp-server/security/advisories/GHSA-jgj3-97w2-9v9r CVE record · GitHub_M · Updated 2026-10-09T17:42:45.100Z
NVD · CVE-2026-107820 · Updated 2026-10-16T16:00:33.533 - https://github.com/duty1g/x64dbg-mcp-server/security/advisories/GHSA-4478-h5jv-647m CVE record · GitHub_M · Updated 2026-10-09T17:42:45.100Z
NVD · CVE-2026-107820 · Updated 2026-10-16T16:00:33.533 - https://github.com/duty1g/x64dbg-mcp-server/commit/0dd4204d37c81d8b605133dc48c14886eeac1562 CVE record · GitHub_M · Updated 2026-10-09T17:42:45.100Z
NVD · CVE-2026-107820 · Updated 2026-10-16T16:00:33.533 - https://github.com/duty1g/x64dbg-mcp-server/releases/tag/v1.2 CVE record · GitHub_M · Updated 2026-10-09T17:42:45.100Z
NVD · CVE-2026-107820 · Updated 2026-10-16T16:00:33.533