CVE-2026-47427
GitHub MCP Server: Nil Pointer Dereference DoS in completion/complete Handler
CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
0th
GitHub MCP Server is GitHub's official MCP Server. Prior to 1.1.0, the CompletionsHandler function in pkg/github/server.go accesses params.Ref without first checking whether it is nil, so a completion/complete request with a missing or empty ref field triggers a nil pointer dereference and a Go runtime panic; because the crash occurs before any authentication or token validation, any unauthenticated client able to send JSON-RPC messages can crash the server, resulting in a complete denial of service. This issue is fixed in version 1.1.0.
| CWE | CWE-476 |
| Vendor | github |
| Product | github-mcp-server |
| Ecosystems | |
| Industries | Technology |
| Published | Jul 28, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
github / github-mcp-server
< 1.1.0
References
github.com: https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7 github.com: https://github.com/github/github-mcp-server/pull/2502 github.com: https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58 github.com: https://github.com/github/github-mcp-server/releases/tag/v1.1.0