CVE-2026-121544

Medium CVSS 4.9

Published 2026-11-03 · last changed 2026-11-03

The fix

We hold no Microsoft remediation data for CVE-2026-121544, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

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.

Sources

NVD record for CVE-2026-121544

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N