CVE-2026-121544

Koodo Reader through 2.4.6 contains a path traversal vulnerability in the self-hosted HTTP server's OPDS handlers that allows authenticated attackers to read files outside the upload directory. Attackers can upload a crafted books.db with a cover value containing ../ sequences, then request /opds/cover/{key} to read files accessible to the server process.

An authenticated attacker can read arbitrary files accessible to the server process, potentially exposing sensitive data including configuration and credentials.

Update Koodo Reader to a version later than 2.4.6 and restrict the server process permissions to the minimum necessary.