pgEdge Postgres MCP Server: Missing Origin validation enables DNS rebinding

Summary

pgEdge Postgres MCP Server before 1.1.0 did not validate the Origin header on its HTTP transport. A user who visits an attacker-controlled web page can be targeted through DNS rebinding, which lets the page reach the locally running server. The attacker can then read schemas and query results from the configured PostgreSQL databases. The issue requires the HTTP transport to be enabled on a machine that also runs a browser; the default stdio transport is not reachable through this path.

Affected

• pgEdge pgedge-postgres-mcp, all versions before 1.1.0
• Only deployments with the HTTP transport enabled

Fixed in

• Version 1.1.0 (validates the Origin header and rejects unexpected origins with 403 Forbidden)

Workaround

• Switch the transport back to stdio where HTTP is not required
• Disable the HTTP transport on workstations where a browser is used
• No other vendor workaround is known.

Exploitation

• No evidence of exploitation in the wild is known.
• A public PoC listing exists but is unverified.
• The vulnerability is not known to be in CISA KEV.

Our recommendation

• Upgrade to pgEdge Postgres MCP Server 1.1.0 or later on all hosts where the HTTP transport is enabled.
• If the web client is served under a hostname, add that origin to http.allowed_origins after upgrading, otherwise browser requests will be refused.
• Where HTTP is not needed, set the transport to stdio.
• Inventory hosts running pgedge-postgres-mcp and record transport mode and version.
• Limit database credentials held on workstations that run a browser.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

• GitHub security advisory GHSA-6hg5-9f3w-c886 github.com
• Fix commit 5571bd4 github.com
• Issue #231: Validate the Origin header github.com
• Pull request #232 github.com
• Release v1.1.0 github.com
• pgEdge documentation: Security (v1.1.0) docs.pgedge.com

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 18:40.