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OpenAdvisories
High · 7.5 CVE-2026-47427 EUVD-2026-49875GHSA-w4q6-qw23-4rg7GO-2026-6118

GitHub MCP Server: Nil Pointer Dereference DoS in completion/complete Handler

Published Jul 28, 2026 · Updated Jul 28, 2026 · Assigned by GitHub_M

Description

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.

Affected products

VendorProductAffectedFixed
github github-mcp-server < 1.1.0 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
SLES for SAP 16.0 govulncheck-vulndb 0.0.20260827T195228-160000.1.1 SUSE-SU-2026:23625-1
SLES 16.0 govulncheck-vulndb 0.0.20260827T195228-160000.1.1 SUSE-SU-2026:23625-1
ReleasePackageFixed inAdvisory
openSUSE Leap 16.0 govulncheck-vulndb 0.0.20260827T195228-160000.1.1 openSUSE-SU-2026:21761-1

Affected packages

EcosystemPackageAffectedFixedRecord
Go github.com/github/github-mcp-server < 1.1.0 1.1.0 GHSA-w4q6-qw23-4rg7

Advisories 2

References