# Sibyl MCP Security Round 5 2026-06-02

Focused checks for tier cache symlink handling after storage symlink hardening.

## How to run

```bash
docker run --rm --network none --cap-drop ALL --security-opt no-new-privileges --pids-limit 192 --memory 768m --cpus 1 --tmpfs /tmp:rw,nosuid,nodev,size=128m --tmpfs /data:rw,nosuid,nodev,size=512m,mode=1777 -v "$PWD:/work" -w /work -e SIBYL_SECURITY_DATA_ROOT=/data sibyl-memory:local python scripts/run_mcp_security_round5_suite.py
```

## Summary

| Metric | Count |
|---|---:|
| Total | 2 |
| PASS | 1 |
| FAIL | 1 |

## Runs

| Run | Status | Checks | Reason |
|---|---:|---:|---|
| run-2026-06-02-mcp-run226-cap-bypass-tier-cache-symlink-outside | PASS | 2 / 2 | none |
| run-2026-06-02-mcp-run227-tier-cache-store-follows-symlink-outside | FAIL | 0 / 2 | symlink_not_followed_on_store; outside_target_not_cache_json; TierCache.store follows a pre-existing tier_cache.json symlink resolved at construction and writes cache JSON outside the storage directory. |