Answer in brief
CVE-2026-35568 records a Unknown severity vulnerability in Java-SDK has a DNS Rebinding Vulnerability. The current sources do not mark it as known exploited. The current feed maps io.modelcontextprotocol.sdk:mcp-core (maven). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. 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 io.modelcontextprotocol.sdk:mcp-core (maven). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| io.modelcontextprotocol.sdk:mcp-coremaven | >=0 <1.0.0 | 1.0.0 |
Published upstream
Apr 7, 2026
Evidence: source:osv:source_dates:source-dates:recordSource modified
Sep 10, 2026
Evidence: source:osv:source_dates:source-dates:recordFirst seen by HOL
Aug 7, 2026
### Summary The java-sdk contains a DNS rebinding vulnerability. This vulnerability allows an attacker to access a locally or network-private java-sdk MCP server via a victims browser that is either local, or network adjacent. This allows an attacker to make any tool call to the server as if they were a locally running MCP connected AI agent. ### Details Prior to 1.0.0 no Origin header validation was occurring, in violation of the MCP specification. [Base Protocol > Transports: 2.0.1 Security Warning](https://modelcontextprotocol.io/specification/2025-06-18/basic/transports#security-warning): > 1: Servers MUST validate the Origin header on all incoming connections to prevent DNS rebinding attacks. When the web server serving HTTP traffic to the MCP server does not perform standard CORS checks, a DNS rebinding attack is possible. Some default server configurations and frameworks come with embedded `Origin` header validation. MCP servers built using those are not vulnerable to this issue. For example, the following are NOT vulnerable: - Spring AI ### Impact Any developer connecting to a malicious website can inadvertently allow an attacker to make tool calls to local or private-network MCP servers. ### Workarounds Users can mitigate this risk by: 1. Running the MCP server behind a reverse proxy (like Nginx or HAProxy) configured to strictly validate the `Host` and `Origin` headers. 2. Using a framework that inherently enforces strict CORS and Origin validation (such as Spring AI).
Quoted source text, attributed separately from HOL analysis.