CVE-2024-4358

CVE-2024-4358 is a critical (CVSS 9.8) authentication bypass by spoofing (CWE-290) in Progress Telerik Report Server 2024 Q1 (10.0.24.305) and earlier when the server is deployed on IIS. The flaw is reachable over the network with no privileges and no user interaction, so a remote, unauthenticated attacker can spoof a valid session to reach Report Server functionality that should require sign-in; public reporting indicates this can be abused to create rogue administrator accounts and take over the instance. Access to restricted functionality and administrative control is the immediate gain, and per a released public proof of concept the bypass can be chained with the CVE-2024-1800 deserialization flaw to achieve unauthenticated remote code execution. Any organization running Telerik Report Server 2024 Q1 or earlier on IIS is affected. Exploitation is confirmed in the wild: CISA added the bug to the KEV catalog on 2024-06-13, and the 97.5% EPSS score (100th percentile) signals a very high likelihood of continued exploitation, though ransomware use is listed as unknown.

What to do: Upgrade every Telerik Report Server instance to Progress' fixed release (2024 Q2, 10.0.24.414, or later per the vendor advisory); if prompt patching is not possible, CISA's required action is to apply vendor mitigations or discontinue use of the product. Audit the Users/Administrators list for rogue admin accounts, review IIS logs for unauthenticated requests to restricted endpoints, and inventory for any instances hosted on IIS. If your deployment is also exposed to CVE-2024-1800, patch that as well, since the public PoC chains the two flaws for unauthenticated RCE.