CVE-2026-55604 | DeepSeek MCP Server is an MCP server for DeepSeek V4. Starti… | CVSS 8.6 HIGH

Description

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.

Metadata

CVE ID: CVE-2026-55604
State: PUBLISHED
Assigner: GitHub_M
Reserved: 2026-06-16 23:31 UTC
Published: 2026-07-09 21:13 UTC
Last updated: 2026-07-09 21:13 UTC
Primary CWE: CWE-639
CWE-639: Authorization Bypass Through User-Controlled Key
Vendor / Product: arikusi / deepseek-mcp-server
Sources: cve.org · NVD

Severity & Metrics

8.6 HIGH CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

Affected products (1)

Vendor	Product	Platform	Versions
arikusi	deepseek-mcp-server	—	>= 1.4.2, < 1.7.0

Weakness (CWE)

CWE	Source	Description
CWE-639	cna	CWE-639: Authorization Bypass Through User-Controlled Key

CVSS scores (1)

Score	Severity	Version	Source	Vector
8.6	HIGH	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

References (2)

https://github.com/arikusi/deepseek-mcp-server/security/advisories/GHSA-fh3r-g96v-f578 https://github.com/arikusi/deepseek-mcp-server/security/advisories/GHSA-fh3r-g96v-f578
https://github.com/arikusi/deepseek-mcp-server/releases/tag/v1.7.0 https://github.com/arikusi/deepseek-mcp-server/releases/tag/v1.7.0