[GHSA] GHSA-phj3-59pf-cp83 (high) — Thumbor proportion filter allows unbounded post-transform resize leading to remote DoS

GHSA-phj3-59pf-cp83 Severity: high CVE: CVE-2026-53505

Thumbor proportion filter allows unbounded post-transform resize leading to remote DoS

### Summary Thumbor's `filters:proportion(<value>)` filter does not enforce an upper bound on `<value>` and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service.

### Details