Improper verification of cryptographic signature issue exists in "FreeFrom - the nostr client" App versions prior to 1.3.5 for Android and iOS. The affected app cannot detect event data with invalid signatures.
https://play.google.com/store/apps/details?id=com.freefrom
https://jvn.jp/en/jp/JVN55045256/
https://apps.apple.com/us/app/freefrom-the-nostr-client/id6446819930