{"action":"Upgrade io.modelcontextprotocol.sdk:mcp-core to 0.18.3 (0.18.x), 1.0.1 (1.0.x) or 1.1.1 (1.1.x) or later.","affected":[{"fixed":"1.0.1","introduced":"1.0.0"},{"fixed":"1.1.1","introduced":"1.1.0"},{"fixed":"0.18.3","introduced":"0"}],"component":"io.modelcontextprotocol.sdk:mcp-core","cve_ids":["CVE-2026-34237"],"ecosystem":"Maven","epss":0.00222,"exploited":false,"fixed_versions":["1.0.1","1.1.1","0.18.3"],"ghsa_id":"GHSA-hv2w-8mjj-jw22","id":"tcs_01M5N91ASQ0JWQSPDT7G53VPKW","modified_at":"2026-09-10T03:50:39.742363136Z","published_at":"2026-03-30T17:26:44Z","references":["https://osv.dev/vulnerability/GHSA-hv2w-8mjj-jw22","https://github.com/modelcontextprotocol/java-sdk/security/advisories/GHSA-hv2w-8mjj-jw22","https://nvd.nist.gov/vuln/detail/CVE-2026-34237","https://cheatsheetseries.owasp.org/cheatsheets/HTTP_Headers_Cheat_Sheet.html#access-control-allow-origin","https://github.com/modelcontextprotocol/java-sdk","https://github.com/modelcontextprotocol/java-sdk/blob/main/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProvider.java#L289","https://github.com/modelcontextprotocol/java-sdk/blob/main/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletStreamableServerTransportProvider.java#L525"],"severity":{"label":"medium","score":6.1},"sources":[{"source":"osv","source_id":"GHSA-hv2w-8mjj-jw22","url":"https://osv.dev/vulnerability/GHSA-hv2w-8mjj-jw22"}],"summary":"MCP Java SDK has a Hardcoded Wildcard CORS (Access-Control-Allow-Origin: *)"}