CVE-2026-47427
GitHub MCP Server: Nil Pointer Dereference DoS in completion/complete Handler
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.
INFO
Published Date :
July 28, 2026, 4:18 p.m.
Last Modified :
Aug. 8, 2026, 1:24 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE |
Solution
- Update GitHub MCP Server to version 1.1.0.
- Apply vendor patches immediately.
- Monitor server for stability.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-47427.
| URL | Resource |
|---|---|
| https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58 | Patch |
| https://github.com/github/github-mcp-server/pull/2502 | Issue Tracking Patch |
| https://github.com/github/github-mcp-server/releases/tag/v1.1.0 | Release Notes |
| https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7 | Exploit Vendor Advisory |
| https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7 | Exploit Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-47427 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-47427
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-47427 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-47427 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Aug. 08, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:github:mcp_server:*:*:*:*:*:*:*:* versions up to (excluding) 1.1.0 Added Reference Type GitHub, Inc.: https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/github/github-mcp-server/pull/2502 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://github.com/github/github-mcp-server/releases/tag/v1.1.0 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7 Types: Exploit, Vendor Advisory Added Reference Type CISA-ADP: https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7 Types: Exploit, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 28, 2026
Action Type Old Value New Value Added Reference https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7 Added SSVC {'id': 'CVE-2026-47427', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-28T17:31:12.371732Z'} -
New CVE Received by [email protected]
Jul. 28, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'github', 'product': 'github-mcp-server', 'versions': [{'status': 'affected', 'version': '< 1.1.0'}]}] Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-476 Added Reference https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58 Added Reference https://github.com/github/github-mcp-server/pull/2502 Added Reference https://github.com/github/github-mcp-server/releases/tag/v1.1.0 Added Reference https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7