{"id":"CVE-2026-55604","aliases":["GHSA-fh3r-g96v-f578"],"url":"https://o3.security/vulnerability/CVE-2026-55604","summary":"@arikusi/deepseek-mcp-server has an Authorization Bypass Through User-Controlled Key","details":"DeepSeek MCP Server is an MCP server for DeepSeek V4. Starting in version 1.4.2 and prior to version 1.7.0, the process-global `SessionStore` accepts caller-supplied `session_id` values without binding them to any authenticated principal or transport session. An attacker can enumerate active session IDs via `deepseek_sessions`, then reuse a victim-controlled `session_id` in `deepseek_chat` to retrieve and continue the victim's conversation context. Version 1.7.0 contains a patch.","published":"2026-07-09T21:13:15.713Z","modified":"2026-08-12T03:51:22.430379515Z","cvss":{"score":8.6,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"@arikusi/deepseek-mcp-server","fixedVersion":"1.7.0"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/arikusi/deepseek-mcp-server/releases/tag/v1.7.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55604.json"},{"type":"ADVISORY","url":"https://github.com/arikusi/deepseek-mcp-server/security/advisories/GHSA-fh3r-g96v-f578"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55604"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:22.430379515Z"}}