CVE-2026-47427: github github-mcp-server NULL Pointer Dereference
Vulnerability summary
CVE-2026-47427 is a high (CVSS 7.5) NULL Pointer Dereference vulnerability in github github-mcp-server. EPSS estimates a 0.77% chance of exploitation in the next 30 days, higher than 54.9% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 2 · Related 2Timeline
- 28-07-2026PublishedVulnerability first disclosed.
- 28-07-2026Last modifiedVulnerability information updated.
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 metrics
3 scores · 3 sources · 1 version- OSV · GoEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.77%
Chance of exploitation in the next 30 days
Percentile
55%
Versus all other CVEs
30-day change
+0.33 pp
From 0.44% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundGithub Mcp Server
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Github2 products
- github-mcp-server< 1.1.0
- mcp_server< 1.1.0
Github.com/github1 product
- github-mcp-server< 1.1.0
2 vendors · 3 products
References
5 links- github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7X Refsource CONFIRMWEBAdvisoryExploitVendor Advisory
- github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58X Refsource MISCWEBFIXPatch