CVE-2026-47427
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.44%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.44% probability · 37th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-476
- Affected
- github/mcp server
- Source
- security-advisories@github.com
References
- https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58Patch
- https://github.com/github/github-mcp-server/pull/2502Issue Tracking, Patch
- https://github.com/github/github-mcp-server/releases/tag/v1.1.0Release Notes
- https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7Exploit, Vendor Advisory
- https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7Exploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.