gcdRadar
archive/Patch now/AIR-2026-1220
closedclosed 29 Jul 2026Patch now2 Disclosed vulnerabilityAI

CVE-2026-63118: DNS Rebinding Vulnerability in MCP Ruby SDK

mcp gem

An HTTP Host header validation flaw in the MCP Ruby SDK allows malicious web pages to use DNS rebinding to interact with local Model Context Protocol servers. The issue was resolved in version 0.23.0.

disclosed CVENo confirmed exploitation, so this record is tracked as a disclosed vulnerability and not counted as an incident. It moves into the counts if CISA or the vendor confirms exploitation. Why

CVSS
6.9
EPSS
<0.01 · top 85% · 2026-11-13
EPSS scores by FIRST
fix status
Fix status unknown
first report
29 Jul 2026
last update
29 Jul 2026
CVE ids
CVE-2026-63118other records

Timeline · 1

  1. 29 Jul 2026CVE-2026-63118: MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients.

Sources · 1

Advisories and databases

  1. 2026-07-29
    CVE-2026-63118: MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients.
    NVD · nvd.nist.gov/vuln/detail/CVE-2026-63118

Titles and links belong to their publishers. The summary above is written by gcdRadar in its own words; data is CC BY-SA 4.0.

Classification

lane
Patch now
AI role
Attack on AI
categories
Infrastructure vulnerability
severity
2 · Disclosed vulnerability
fix status
Fix status unknown
targets
Framework / tooling
owasp llm top 10
LLM03:2025 Supply Chain
mitre atlas
no technique for these categories
tags
mcpdns-rebinding
dates
happened 29 Jul 2026 · first reported 29 Jul 2026
origin
NVD
Vulnerability record from NVD / the GitHub Advisory Database. This product uses the NVD API but is not endorsed or certified by the NVD.
record
confidence 0.95 · created 2026-10-18 10:04Z · updated 2026-10-18 10:04Z

Lane, AI role, categories and severity come from the classifier; the OWASP and ATLAS rows are derived from the categories. How these are assigned

Copy a brief

This record as a short Markdown brief, for a ticket, a chat or a coding agent.

the brief as text
# CVE-2026-63118: DNS Rebinding Vulnerability in MCP Ruby SDK

https://gcdradar.vercel.app/incidents/cve-2026-63118-dns-rebinding-vulnerability-in-mcp-ruby-sdk · AIR-2026-1220 · closed 2026-07-29

- Lane: Patch now
- Severity: 2 (Disclosed vulnerability)
- Fix status: Fix status unknown
- First reported: 2026-07-29
- AI role: Attack on AI
- Products: mcp gem
- CVE ids: CVE-2026-63118
- CVSS: 6.9

## Summary

An HTTP Host header validation flaw in the MCP Ruby SDK allows malicious web pages to use DNS rebinding to interact with local Model Context Protocol servers. The issue was resolved in version 0.23.0.

## What to do

No action recorded; read the sources below and the vendor's advisory.

## Latest updates

- 2026-07-29: CVE-2026-63118: MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. (https://nvd.nist.gov/vuln/detail/CVE-2026-63118)

## Sources

- 2026-07-29 NVD: CVE-2026-63118: MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. https://nvd.nist.gov/vuln/detail/CVE-2026-63118

Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.

Related

  1. closed6.2
    MCP SDKs CVE-2026-63119: Unbounded IO Read Vulnerability in MCP Ruby SDK

    Patch now · Disclosed · since 29 Jul 2026 · CVE-2026-63119

    AI
  2. closed7.5
    MCP SDKs CVE-2026-67432: Unbounded JSON-RPC Request Vulnerability in MCP Ruby SDK

    Patch now · Disclosed · since 29 Jul 2026 · CVE-2026-67432

    AI
  3. closed5.3
    MCP SDKs CVE-2026-67430: Memory Exhaustion Vulnerability in MCP Ruby SDK

    Patch now · Disclosed · since 29 Jul 2026 · CVE-2026-67430

    AI
  4. closed8.3
    MCP SDKs CVE-2026-67431: Session Hijacking Vulnerability in MCP Ruby SDK

    Patch now · Disclosed · since 29 Jul 2026 · CVE-2026-67431

    AI
  5. closed7.5
    Langflow CVE-2026-18899: IBM Langflow OSS path traversal vulnerability

    Patch now · Disclosed · since 28 Aug 2026 · CVE-2026-18899

    AI
  6. closed8.8
    Langflow CVE-2026-18729: IBM Langflow OSS code generation control vulnerability

    Patch now · Disclosed · since 28 Aug 2026 · CVE-2026-18729

    AI