https://vulnerability.circl.lu/sightings/feed 2026-08-01T03:49:42.261588+00:00 Vulnerability-Lookup info@circl.lu python-feedgen Contains only the most 10 recent sightings. https://vulnerability.circl.lu/sighting/4f83b35a-643c-4d9f-bc95-3837c0f38dc4/export 2026-08-01T03:49:42.282736+00:00 Automation user https://cve.circl.lu/user/automation {"uuid": "4f83b35a-643c-4d9f-bc95-3837c0f38dc4", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-63118", "type": "seen", "source": "https://gist.github.com/alon710/f097a8ec4fd3160f0611d4f0d84400e7", "content": "# CVE-2026-63118: CVE-2026-63118: DNS-Rebinding and Cross-Origin Request Execution in Model Context Protocol (MCP) Ruby SDK\n\n> **CVSS Score:** 6.9\n> **Published:** 2026-07-30\n> **Full Report:** https://cvereports.com/reports/CVE-2026-63118\n\n## Summary\nA critical vulnerability (CVE-2026-63118) in the Model Context Protocol (MCP) Ruby SDK allows attackers to execute arbitrary JSON-RPC commands and exfiltrate sensitive local data from an MCP server bound to the local loopback interface. This is achieved through DNS-rebinding and cross-origin request execution due to missing validation of the HTTP Host and Origin headers in the StreamableHTTPTransport component.\n\n## TL;DR\nA DNS-rebinding flaw in the MCP Ruby SDK (< 0.23.0) allows malicious sites to bypass the browser Same-Origin Policy and run arbitrary local tools.\n\n## Exploit Status: POC\n\n## Technical Details\n\n- **CWE ID**: CWE-346, CWE-350\n- **Attack Vector**: Network (AV:N)\n- **CVSS Score**: 6.9 (Medium)\n- **Exploit Status**: PoC Available\n- **Affected Component**: StreamableHTTPTransport\n- **Fixed Version**: v0.23.0\n- **CISA KEV Status**: Not Listed\n\n## Affected Systems\n\n- Model Context Protocol (MCP) Ruby SDK (mcp gem)\n- **mcp**: < 0.23.0 (Fixed in: `v0.23.0`)\n\n## Mitigation\n\n- Upgrade the mcp gem to version 0.23.0 or higher.\n- Configure upstream Host and Origin validation in reverse proxies.\n- Restrict server binds strictly to the loopback interface (127.0.0.1 or ::1).\n\n**Remediation Steps:**\n1. Modify the Gemfile to require 'mcp' version 0.23.0 or higher.\n2. Run 'bundle update mcp' to apply the update.\n3. Optionally define 'allowed_hosts' and 'allowed_origins' parameters if binding to non-loopback interfaces.\n\n## References\n\n- [GHSA-rjr6-rcgv-9m7m: DNS-rebinding and cross-origin request execution in MCP Ruby SDK](https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-rjr6-rcgv-9m7m)\n- [CVE-2026-63118 Record](https://www.cve.org/CVERecord?id=CVE-2026-63118)\n- [NVD - CVE-2026-63118 Detail](https://nvd.nist.gov/vuln/detail/CVE-2026-63118)\n\n\n---\n*Generated by [CVEReports](https://cvereports.com/reports/CVE-2026-63118) - Automated Vulnerability Intelligence*", "creation_timestamp": "2026-07-31T07:31:42.012680Z"} 2026-07-31T07:31:42.012680+00:00 https://vulnerability.circl.lu/sighting/b5fb0395-3e14-44c3-a464-84b0b9e78485/export 2026-08-01T03:49:42.286064+00:00 Joseph Lee https://cve.circl.lu/user/syspect {"uuid": "b5fb0395-3e14-44c3-a464-84b0b9e78485", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "86ecb4e1-bb32-44d5-9f39-8a4673af8385", "vulnerability": "CVE-2026-63118", "type": "published-proof-of-concept", "source": "https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-rjr6-rcgv-9m7m", "content": "", "creation_timestamp": "2026-07-30T16:35:30.654080Z"} 2026-07-30T16:35:30.654080+00:00 https://vulnerability.circl.lu/sighting/5d394ead-5b5a-4f38-b887-2546653c03c0/export 2026-08-01T03:49:42.287061+00:00 Automation user https://cve.circl.lu/user/automation {"uuid": "5d394ead-5b5a-4f38-b887-2546653c03c0", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-63118", "type": "seen", "source": "https://bsky.app/profile/cve.skyfleet.blue/post/3mrssjm3jv424", "content": "CVE-2026-63118 - MCP Ruby SDK: Streamable HTTP transport lacks DNS-rebinding (Host/Origin) protection\nCVE ID : CVE-2026-63118\n \n Published : July 29, 2026, 8:17 p.m. | 26\u00a0minutes ago\n \n Description : MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and ...", "creation_timestamp": "2026-07-29T20:51:38.481124Z"} 2026-07-29T20:51:38.481124+00:00