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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-47427
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-28 16:18:14 UTC
Updated2026-08-08 01:24:51 UTC
DescriptionGitHub 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

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

EPSS: 0.003940000 probability, percentile 0.322580000 (date 2026-08-03)

Problem Types: CWE-476 | CWE-476 CWE-476: NULL Pointer Dereference

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

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

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Github Mcp Server All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Github Github-mcp-server affected < 1.1.0 Not specified

References

ReferenceSourceLinkTags
github.com/github/github-mcp-server/pull/2502 [email protected] github.com Issue Tracking, Patch
github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com Exploit, Vendor Advisory
github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee6... [email protected] github.com Patch
github.com/github/github-mcp-server/releases/tag/v1.1.0 [email protected] github.com Release Notes
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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