Admin-editable blueprint field patterns go through `new RegExp(pattern).test(userValue)`
— a classic ReDoS sink if the admin account is compromised or the
permission is ever delegated. A pattern like `^(a+)+$` against 30
'a's followed by '!' freezes the event loop for seconds per request.
Three layers of defence:
- Save-time: FieldValidationSchema.pattern now has `.max(200)` and a
`.refine()` that rejects nested-quantifier shapes like `(x+)+`,
`(?:x*)+`, `(x{2,})*`.
- Runtime (engine/blueprint/validator.ts):
- isSuspectRegexPattern() runs the same heuristic. If it fires, the
field fails validation outright — regex is never compiled.
- Input strings are sliced to 4096 chars before .test() so even a
benign pattern against a 10 MB payload returns in < 50 ms.
- RegExp compile failures are caught and treated as validation
errors rather than crashing the request.
Tests: 10 cases in packages/engine/src/__tests__/blueprint-validator-redos.test.ts,
including the canonical `^(a+)+$` attack — completes in < 50 ms.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
