A malicious or compromised Flatpak repository can write attacker-controlled content to arbitrary locations on the host filesystem via extract_extra_data(). On system installs, the write happens as root. Two issues combine: `files/extra` is resolved via path operations that follow symlinks, and blob names from `xa.extra-data-sources` are not sanitized against `..` traversal.
https://access.redhat.com/errata/RHSA-2026:95493
https://access.redhat.com/errata/RHSA-2026:92369
https://access.redhat.com/errata/RHSA-2026:92221
https://access.redhat.com/errata/RHSA-2026:90364
https://access.redhat.com/errata/RHSA-2026:89733
https://access.redhat.com/errata/RHSA-2026:80687