Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, 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. This issue is fixed in 7.8.0.
https://github.com/thumbor/thumbor/security/advisories/GHSA-phj3-59pf-cp83
https://github.com/thumbor/thumbor/releases/tag/7.8.0
https://github.com/thumbor/thumbor/commit/2c716119de986cfc68c7071af52a98187e006023