VDB-383917 · CVE-2026-47427 · GCVE-0-2026-47427

GitHub MCP Server up to 1.0.x Completion pkg/github/server.go CompletionsHandler Ref null pointer dereference

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.1	$0-$5k	3.33

Summaryinfo

A vulnerability identified as problematic has been detected in GitHub MCP Server up to 1.0.x. The affected element is the function CompletionsHandler of the file pkg/github/server.go of the component Completion Handler. This manipulation of the argument Ref causes null pointer dereference. This vulnerability is tracked as CVE-2026-47427. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in GitHub MCP Server up to 1.0.x and classified as problematic. Affected by this vulnerability is the function CompletionsHandler of the file pkg/github/server.go of the component Completion Handler. The manipulation of the argument Ref with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-47427 since 05/19/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available.

Upgrading to version 1.1.0 eliminates this vulnerability.

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Productinfo

Type

Bug Tracking Software

Vendor

GitHub

Name

MCP Server

Version

License

open-source

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: MCP Server 1.1.0

Timelineinfo

05/19/2026 CVE reserved
07/28/2026 +70 days Advisory disclosed
07/28/2026 +0 days VulDB entry created
07/28/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-47427 (🔒)
GCVE (CVE): GCVE-0-2026-47427
GCVE (VulDB): GCVE-100-383917

Entryinfo

Created: 07/28/2026 18:37
Changes: 07/28/2026 18:37 (59)
Complete: 🔍
Cache ID: 216::103