# mcp (RubyGems) vulnerabilities

6 known vulnerabilities (3 high, 3 medium), with the versions each affects and the releases that fix them.

## At a glance

- Latest release: not known (cve.now hasn't read this package's releases)
- Newest unaffected release: not known without release data
- Registry: https://rubygems.org/gems/mcp

## Advisories (6)

### [CVE-2026-67432](https://cve.now/CVE-2026-67432): MCP Ruby SDK: Unbounded JSON-RPC request body causes uncontrolled memory allocation in StreamableHTTPTransport

- Severity: High 7.5
- Published: Jul 29, 2026
- Affected: fixed in 0.23.0.

### [CVE-2026-67431](https://cve.now/CVE-2026-67431): MCP Ruby SDK: Ruby SSE Session Poisoning

- Severity: High 8.3
- Published: Jul 29, 2026
- Affected: fixed in 0.23.0.

### [CVE-2026-63119](https://cve.now/CVE-2026-63119): MCP Ruby SDK: Unbounded line buffer in stdio transports leads to memory exhaustion (DoS)

- Severity: Medium 6.2
- Published: Jul 29, 2026
- Affected: fixed in 0.23.0.

### [CVE-2026-67430](https://cve.now/CVE-2026-67430): MCP Ruby SDK: Unbounded session retention in StreamableHTTPTransport allows memory exhaustion via initialize flood

- Severity: Medium 5.3
- Published: Jul 29, 2026
- Affected: fixed in 0.23.0.

### [CVE-2026-63118](https://cve.now/CVE-2026-63118): MCP Ruby SDK: Streamable HTTP transport lacks DNS-rebinding (Host/Origin) protection

- Severity: Medium 6.9
- Published: Jul 29, 2026
- Affected: fixed in 0.23.0.

### [CVE-2026-33946](https://cve.now/CVE-2026-33946): MCP Ruby SDK: Insufficient Session Binding Allows SSE Stream Hijacking via Session ID Replay

- Severity: High 8.2
- Published: Mar 27, 2026
- Affected: fixed in 0.9.2.

---

Source: cve.now
Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards.
Page: https://cve.now/packages/rubygems/mcp
Site guide for agents: https://cve.now/llms.txt
Uses NVD data; not endorsed by NVD.