v5.1.2 — SymPy Expression Injection Fix (CWE-95, CVSS 8.8)

v5.1.2 — Security Patch

This is an emergency patch release. Fixes a High severity (CVSS 8.8) authenticated RCE vulnerability (CWE-95) in SymPy's parse_expr() across all math verification paths.

Security

• CWE-95 mitigation: Added safe_parse_expr() — denylist + stripped __builtins__ + allow-listed math namespace + per-call global dict copy + pre/post-parse validation. Replaced all direct parse_expr() call sites in main.py, verifier.py, batch.py, and validator.py.
• Calculus symbol consistency: Added get_safe_symbol() to match SymPy symbol assumptions (e.g., n as integer=True, positive=True) — prevents incorrect diff/integrate/limit results.
• Defense-in-depth: Pre-parse AST depth limit, post-parse SymPy tree depth validation, sympy.Expr type enforcement (rejects relationals like x < y), extra_symbols key/value validation, sanitized exception handling.

Fixes

• Cache Redis fail-closed: Enforced fail-closed Redis backend for distributed cache mode (#199)
• CodSpeed benchmarks: Performance benchmark workflow added (#198)
• TS SDK: Restored package-lock.json for reliable npm ci in publish workflow (#197)

Version Updates

Artifact	Version
qwed (PyPI)	5.1.2
qwed_sdk (Python)	5.1.2
@qwed-ai/sdk (NPM)	5.1.2
qwed (Rust crate)	5.1.2
API version header	5.1.2
Docker image	docker.io/qwedai/qwed-verification:5.1.2

Included PRs

• #197 fix(ts-sdk): lockfile restore
• #198 ci: CodSpeed benchmarks
• #199 fix(cache): fail-closed Redis backend
• #200 fix(math): restrict SymPy expression parsing (CWE-95)
• #201 chore(release): v5.1.2 version bump

Credits: Vulnerability discovered by Sebastion (sebastiondev) via Foundation Machines and independently confirmed by EQSTLab. Fix reviewed and hardened by the QWED team.

Full Changelog: v5.1.1...v5.1.2