Firefly II has Stored XSS in Audit Log Entry view via piggy bank name (ale.twig)
Date: 2026-06
Affected: composer/grumpydictator/firefly-iii
Attack vector: xss
Category: vulnerability-disclosure
Severity: Medium
CWE: CWE-116
CWE-79

## Summary The Twig template `resources/views/list/ale.twig` renders the piggy bank name from `AuditLogEntry.after.piggy` using the `|raw` filter, bypassing Twig's auto-escaping. A piggy bank created with an HTML payload in its name executes arbitrary JavaScript in any browser viewing that transaction's audit log. ## Root Cause The `|raw` filter is required on the outer `trans()` call to preserve `<span>` tags in the `amount` parameter (currency styling). However, this also disables escaping for the user-controlled `name` parameter. **Vulnerable code (`resources/views/list/ale.twig` lines 107, 110):** ```twig {{ trans('firefly.ale_action_log_add', { amount: formatAmountBySymbol(...), name: logEntry.after.piggy })|raw }} ``` No HTML sanitization at storage time — `PiggyBankStoreRequest` only validates `min:1|max:255|uniquePiggyBankForUser`. ## Data Flow ``` POST /api/v1/piggy-banks {"name": "<img src=x onerror=...>"} → Stored verbatim in piggy_banks.name → Transaction rule fires add_to_piggy / remove_from_piggy → UpdatePiggyBank::handle() stores AuditLogEntry.after.piggy = raw name → Any user views /transactions/show/{id} → ale.twig outputs unescaped payload → XSS fires ``` ## CSP Note The nonce-based CSP (`script-src 'nonce-...' 'strict-dynamic'`) does **not** prevent this attack. Inline event handlers (`onerror`, `onload`) in HTML attributes are governed by `script-src-attr`, which is unrestricted in the current policy. The `<img onerror=...>` payl


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