Description

Multiple high-severity vulnerabilities in Progress Telerik UI for ASP.NET AJAX can be chained to achieve unauthenticated remote code execution. The affected RadAsyncUpload component contains weaknesses in encrypted client-state processing, timing validation, upload metadata protection, and unsafe type resolution. Successful exploitation could allow a remote attacker to execute arbitrary code with the privileges of the web application's application pool identity. The attack chain centers on CVE-2026-13182, an AES-CBC padding-oracle vulnerability that allows attackers to distinguish decryption failures from invalid JSON processing and potentially forge encrypted client-state data. CVE-2026-13183 provides a related timing oracle, while CVE-2026-13184 can expose a predictable default HMAC key when specific cryptographic configuration is absent. The resulting forged upload metadata can then be used with CVE-2026-13181, which permits attacker-controlled AsyncUploadTypeName processing and unsafe type resolution, creating a path to remote code execution. The vulnerabilities affect Telerik UI for ASP.NET AJAX versions 2010.1.309 through 2026.2.519 where the relevant components are used. Progress fixed these issues in version 2026.2.708 (2026 Q2 SP1). Organizations should prioritize upgrading exposed applications, review RadAsyncUpload usage and cryptographic settings, restrict unnecessary access to upload handlers, and disable the handler where it is not required.