CVE-2026-47427

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.8% (54th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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 v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
39
EG Risk 39/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation1% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.8%
EPSS %ILE
54th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

July 28, 2026

Last Modified

August 8, 2026

Advisory Details (4)

Auto-updated Jul 28, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github, github_commit, github_pr.
githubMentions a patch (unverified)🟡 PoC Available

Nil Pointer Dereference DoS in completion/complete Handler · Advisory · github/github-mcp-server · GitHub

https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7
github_release Patch Available

GitHub MCP Server 1.1.0

Patch available: github/github-mcp-server v1.1.0

https://github.com/github/github-mcp-server/releases/tag/v1.1.0
github_pr

fix: guard CompletionsHandler against nil params/ref

Fix merged in github/github-mcp-server PR #2502 on 2026-05-19 — awaiting tagged release

https://github.com/github/github-mcp-server/pull/2502
github_commit

commit c88d2ecdd3bb (github/github-mcp-server)

Fix landed in github/github-mcp-server commit c88d2ecdd3bb — awaiting tagged release

https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58

Vendor Advisories for CVE-2026-47427(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFix by version rangeDependents
github.com/github/github-mcp-server—
  • every version up to 1.1.0: fixed in 1.1.0
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 41× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 121 total refreshes for this CVE.

  1. 2026-10-10 20:00 UTCEPSS rescore
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  1. 2026-09-20 20:16 UTCEPSS rescore
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Related CVEs(same product + same CWE)

Same product

1 shown

Go:github.com/github/github-mcp-server

Frequently asked(5)

What is CVE-2026-47427?
CVE-2026-47427 is a high vulnerability published on July 28, 2026. 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…
When was CVE-2026-47427 disclosed?
CVE-2026-47427 was first published on July 28, 2026, with the most recent update on August 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-47427 actively exploited?
CVE-2026-47427 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (54th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-47427?
CVE-2026-47427 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-47427?
A fix for CVE-2026-47427 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-47427 are linked in the Vendor Advisories panel on this page.

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