In Progress® Telerik® UI for AJAX prior to v2026.2.708, when Telerik.Upload.ConfigurationHashKey is absent and machineKey is not explicitly configured, upload metadata integrity protection may fall back to a predictable default key, enabling attackers to forge protected upload metadata and unlock further exploit chains.

In Progress® Telerik® UI for AJAX prior to v2026.2.708, RadAsyncUpload upload metadata processing may leak cryptographic validity through measurable timing differences, enabling remote attackers to recover protected metadata values.

In Progress® Telerik® UI for AJAX prior to v2026.2.708, RadAsyncUpload client-state processing can distinguish decrypt failures from invalid-JSON parse failures, creating an oracle that reveals protected metadata values to remote attackers.

In Progress® Telerik® UI for AJAX prior to v2026.2.708, forged upload metadata can influence AsyncUploadTypeName processing and trigger unsafe attacker-controlled type resolution, enabling remote code execution in affected deployments.