Answer in brief
CVE-2026-55637 records a High severity (CVSS 0.0) vulnerability in genieacs-mcp: DNS rebinding reaches local GenieACS MCP Streamable HTTP transport. The current sources do not mark it as known exploited. The current feed maps GeiserX/genieacs-mcp (generic), github.com/geiserx/genieacs-mcp (go), github.com/geiserx/genieacs-mcp (go). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 0.0. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps GeiserX/genieacs-mcp (generic), github.com/geiserx/genieacs-mcp (go), github.com/geiserx/genieacs-mcp (go). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| GeiserX/genieacs-mcpgeneric | < 0.3.2 | Not reported |
| github.com/geiserx/genieacs-mcpgo | <=0.3.1 | 0.3.2 |
| github.com/geiserx/genieacs-mcpgo | >=0 <0.3.2 | 0.3.2 |
Published upstream
Aug 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 25, 2026
genieacs-mcp is an MCP server for GenieACS written in Go. Prior to 0.3.2, the Streamable HTTP transport in cmd/server/main.go creates an unauthenticated /mcp listener on the default MCP_LISTEN_ADDR value 127.0.0.1:8080 when MCP_AUTH_TOKEN is unset and the httpSrv.Start(addr) branch does not validate the Host or Origin headers. A malicious website can use DNS rebinding to send browser requests with attacker-controlled Host and Origin values to the loopback listener, initialize an MCP session, list tools, and invoke operations against the GenieACS NBI configured by ACS_URL. Successful exploitation can expose or modify CPE management state, including device reboots, firmware tasks, TR-069 parameter changes, presets, provisions, tags, connection requests, and task operations. The npm wrapper is not affected because it forces TRANSPORT=stdio and does not expose an HTTP listener. This issue is fixed in version 0.3.2.
Quoted source text, attributed separately from HOL analysis.