Answer in brief
CVE-2026-58196 records a Low severity (CVSS 4.7) vulnerability in ToolHive: SSRF in remote MCP server authentication discovery (host-side, bypasses container isolation). The current sources do not mark it as known exploited. The current feed maps stacklok/toolhive (generic), github.com/stacklok/toolhive (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 4.7. 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 stacklok/toolhive (generic), github.com/stacklok/toolhive (go). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| stacklok/toolhivegeneric | <0.31.0 | 0.31.0 |
| github.com/stacklok/toolhivego | <0.31.0 | 0.31.0 |
Published upstream
Sep 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 16, 2026
ToolHive is a utility designed to simplify the deployment and management of Model Context Protocol (MCP) servers. Prior to 0.31.0, remote.Handler.Authenticate in pkg/auth/remote/handler.go invokes discovery.DetectAuthenticationFromServer in pkg/auth/discovery/discovery.go, whose host-side HTTP clients trust remote-server-controlled authentication discovery destinations, follow redirects without host or scheme restrictions, and do not consistently block private addresses. A malicious or compromised remote MCP server can place a resource_metadata URL in WWW-Authenticate for ParseWWWAuthenticate to extract, after which FetchResourceMetadata, OIDC issuer discovery, and well-known discovery can issue GET requests to link-local, RFC1918, or other internal services outside the server's container. The user connects to a server that the user intends to use, but the server controls the internal destination; this path does not depend on the separate NAT64 guard omission because the affected clients did not invoke IsPrivateIP, and it differs from the DCR resolver path that already refused redirects. The demonstrated primitive reaches internal-only HTTP services and reachability or error oracles, and can retrieve AWS metadata credentials where IMDSv1 accepts an unauthenticated GET, while IMDSv2 and GCP metadata prerequisites are not satisfied by the demonstrated request. This vulnerability is fixed in 0.31.0.
Quoted source text, attributed separately from HOL analysis.