{"cve":"CVE-2026-55546","nvd":{"published":"2026-08-25T16:16:55.160","modified":"2026-09-09T21:07:31.353","status":"Deferred","description":"QWED-MCP is a deterministic verification gateway for MCP. Prior to 0.2.1, verify_math_expression() in src/qwed_mcp/engines/math_engine.py passes attacker-controlled expression and claimed_result strings directly to SymPy's parse_expr() after only normalizing caret syntax to Python exponent syntax, without restricting global_dict, removing Python built-ins, or validating the expression AST. Because parse_expr() calls Python's eval() with built-ins available, an attacker who can cause a downstream caller to pass untrusted input to this public library function can use Python import functionality to execute arbitrary operating-system commands as the qwed-mcp process user, read or modify accessible data, exfiltrate process secrets, or reach internal services. The default MCP tool registry does not expose verify_math_expression(), so exploitation requires a downstream integration that invokes the library API with attacker-controlled input. This issue is fixed in version 0.2.1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-94"],"references":["https://github.com/QWED-AI/qwed-mcp/commit/362e61892052e250c56cb1ee852024d6f98c467b","https://github.com/QWED-AI/qwed-mcp/pull/22","https://github.com/QWED-AI/qwed-mcp/releases/tag/v0.2.1","https://github.com/QWED-AI/qwed-mcp/security/advisories/GHSA-mw6r-2hvm-4rp2","https://github.com/QWED-AI/qwed-mcp/security/advisories/GHSA-mw6r-2hvm-4rp2"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:50:17.453294893+00:00"},"epss":{"cve":"CVE-2026-55546","score":0.00726,"percentile":0.54126,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-mw6r-2hvm-4rp2","url":"https://osv.dev/vulnerability/GHSA-mw6r-2hvm-4rp2","summary":"qwed-mcp has Unsafe SymPy `parse_expr()` Remote Code Execution via Unsanitized Math Expression Input","modified":"2026-09-10T12:26:02.991255731Z","packages":[{"ecosystem":"PyPI","name":"qwed-mcp","purl":"pkg:pypi/qwed-mcp","ranges":["<0.2.1"],"fixed":["0.2.1"]}]},{"id":"PYSEC-2026-3915","url":"https://osv.dev/vulnerability/PYSEC-2026-3915","summary":"qwed-mcp has Unsafe SymPy `parse_expr()` Remote Code Execution via Unsanitized Math Expression Input","modified":"2026-09-10T12:15:12.766578464Z","packages":[{"ecosystem":"PyPI","name":"qwed-mcp","purl":"pkg:pypi/qwed-mcp","ranges":["<0.2.1"],"fixed":["0.2.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}