CVE-2026-47427Patch(github / mcp_server)

LOWCVSS 7.5 · HIGH

Exploit discussion active in current signal (1 latest mentions)

Immediate actions

Patch github mcp_server systems immediately
Hunt for exploitation attempts and persistence artifacts
Increase monitoring for publicly documented tradecraft

Recommended action window: High priority (within 72h)

NVD 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.

github CVEs Back to dashboard

2.0/ 10 priority

Sources & remediation

Patch / fix

Exploit / PoC references

Other references

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

Weakness type (CWE)

CWE-476

Priority

LOW

Exploitation

NONE

PoC

YES

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

mcp_server

Threat summary

Public PoC is present in monitored signal
Patch or workaround signal is available
4 mentions across 3 observed days
Momentum state: stable

What's happening

PoC mentioned or linked in 2 signals
Patch or workaround mentioned in 3 signals
Technical details provided in 4 signals
Disclosure: 1 classified signal
Peaked 1d ago at 2 mentions (2026-08-04); latest day: 1
4 total mentions across 3 days

Affected systems

Vendors

github

Products

mcp_server

Deep dive

Activity timeline4 mentions / 3d

Signal classification3 categories

Patch

250.0%

PoC

125.0%

Disclosure

125.0%

Referenced assets2 URLs

By indicator

Classification over time

Date	Total	Labels

2026-08-01	1	Patch1
2026-08-04	2	Patch1PoC1
2026-08-09	1	Disclosure1

Full discourse4 posts

Manthan Ghasadiya@g_m_j_270343d
PoC
Got my 4th CVE published this month: CVE-2026-47427 Unauthenticated DoS in GitHub's official MCP server. One malformed request crashes the whole server. No auth needed. Here's how it works: https://t.co/IR3h23cgFq
Post summary
The tweet announces CVE‑2026‑47427, a unauthenticated DoS affecting GitHub’s MCP server, and points to a link that presumably demonstrates how the vulnerability can be triggered.
11030311
144 followersView on X
Hugo | DevOps | Cybersecurity 🇱🇻@HugoValters46d
Patch
CVE-2026-47427 - Unauthenticated DoS in GitHub MCP Server before 1.1.0. Nil pointer dereference crashes server. CVSS 7.5. Update to 1.1.0 immediately. #CVE #GitHub #infosec #redteam #blueteam #cybersecurity #devsecops #devops #developer #gitlab #git #cybersecuritytips #cybersecuritynews https://www.valtersit.com/cve/CVE-2026-47427
Post summary
The tweet highlights the CVE-2026-47427 DoS vulnerability in GitHub MCP Server and urges users to patch to version 1.1.0 immediately.
10011216
978 followersView on X
Manthan Ghasadiya@g_m_j_270343d
Patch
Credit to @SamMorrowDrums on the GitHub MCP team for picking up the report, assigning the CVE, and shipping the fix in PR #2502. Same lesson I keep hitting across MCP servers: agent tooling ships fast, basic validation gets skipped. A missing nil check becomes a remote crash. Writeup: http://github.com/manthanghasadiya/writeups/tree/main/CVE-2026-47427 More coming.
Post summary
CVE-2026-47427 was discovered, a fix was committed in PR #2502, and a detailed write‑up is linked. No exploit code or active exploitation is reported.
0002051
144 followersView on X
CyberSignal | Cybersecurity News@XQOPTRX39d
Disclosure
🤖 GitHub's official MCP Server vulnerable to unauthenticated DoS CVE-2026-47427 A malformed JSON-RPC completion request can trigger a nil-pointer panic before authentication occurs, allowing a reachable unauthenticated client to crash the MCP server. ✅ Fixed: 1.1.0 🔎 Source: GitHub / Tenable #GitHub #MCP #AISecurity #DoS #CVE
Post summary
The GitHub MCP Server is vulnerable to an unauthenticated DoS caused by a malformed JSON‑RPC request that triggers a nil‑pointer panic; patch 1.1.0 addresses the issue.
0000051
34 followersView on X

CPE platform detail1 entries

Part:

Vendor:

Product:

Version:

Target SW:

Target HW:

1 of 1 entries

Part	Vendor	Product	Version	Target SW	Target HW
App	github	mcp_server	-	-	-

Explore more

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What researchers are saying

CVE-2026-47427

Hugo | DevOps | Cybersecurity 🇱🇻[verified]@HugoValtersPatch

The tweet highlights the CVE-2026-47427 DoS vulnerability in GitHub MCP Server and urges users to patch to version 1.1.0 immediately.

CyberSignal | Cybersecurity News[verified]@XQOPTRXDisclosure

The GitHub MCP Server is vulnerable to an unauthenticated DoS caused by a malformed JSON‑RPC request that triggers a nil‑pointer panic; patch 1.1.0 addresses the issue.

Manthan Ghasadiya@g_m_j_2703PoC

The tweet announces CVE‑2026‑47427, a unauthenticated DoS affecting GitHub’s MCP server, and points to a link that presumably demonstrates how the vulnerability can be triggered.

Manthan Ghasadiya@g_m_j_2703Patch

CVE-2026-47427 was discovered, a fix was committed in PR #2502, and a detailed write‑up is linked. No exploit code or active exploitation is reported.