CVE-2026-47427
HIGHGitHub MCP Server: Nil Pointer Dereference DoS in completion/complete Handler
Title source: cnaDescription
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.
References (4)
Core 4
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7
X_Refsource_Misc x_refsource_misc
https://github.com/github/github-mcp-server/pull/2502
X_Refsource_Misc x_refsource_misc
https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58
X_Refsource_Misc x_refsource_misc
https://github.com/github/github-mcp-server/releases/tag/v1.1.0
Scores
CVSS v3
7.5
EPSS
0.0039
EPSS Percentile
32.2%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-476
Status
published
Products (2)
github/github-mcp-server
0 - 1.1.0Go
github/github-mcp-server
< 1.1.0
Published
Jul 28, 2026
Tracked Since
Jul 28, 2026