The issue was addressed with improved permissions logic. This issue is fixed in macOS Monterey 12.0.1, Security Update 2021-007 Catalina, macOS Big Sur 11.6.1. A malicious application may gain access to a user's Keychain items.
The product does not preserve permissions or incorrectly preserves permissions when copying, restoring, or sharing objects, which can cause them to have less restrictive permissions than intended.