CVE-2026-47427 | GitHub MCP Server is GitHub's official MCP Server. Prior to … | CVSS 7.5 HIGH

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.

Metadata

CVE ID: CVE-2026-47427
State: PUBLISHED
Assigner: GitHub_M
Reserved: 2026-05-19 19:37 UTC
Published: 2026-07-28 15:32 UTC
Last updated: 2026-07-28 17:31 UTC
Primary CWE: CWE-476
CWE-476: NULL Pointer Dereference
Vendor / Product: github / github-mcp-server
Sources: cve.org · NVD

Severity & Metrics

7.5 HIGH CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: PoC
Automatable: yes
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
github	github-mcp-server	—	< 1.1.0

Weakness (CWE)

CWE	Source	Description
CWE-476	cna	CWE-476: NULL Pointer Dereference

CVSS scores (1)

Score	Severity	Version	Source	Vector
7.5	HIGH	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References (4)

https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7 https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7
https://github.com/github/github-mcp-server/pull/2502 https://github.com/github/github-mcp-server/pull/2502
https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58 https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58
https://github.com/github/github-mcp-server/releases/tag/v1.1.0 https://github.com/github/github-mcp-server/releases/tag/v1.1.0