CVE-2022-39313 is a medium-severity vulnerability affecting parse-community's parse-server, an open-source backend framework widely used to build applications on Node.js infrastructure. The vulnerability arises from improper validation of the specified byte range in file download requests (CWE-1284). Specifically, when a client sends a file download request with an invalid byte range, versions of parse-server prior to 4.10.17 and versions from 5.0.0 up to but not including 5.2.8 will crash. This crash leads to a Denial of Service (DoS) condition, as the server becomes unavailable to legitimate users. The root cause is the failure to properly validate and sanitize the byte range input before processing the file download, which causes the server process to terminate unexpectedly. The issue has been addressed in versions 4.10.17 and 5.2.8, where input validation has been improved to prevent server crashes. No known exploits have been reported in the wild, and no workarounds exist aside from upgrading to patched versions. The vulnerability does not require authentication or user interaction, as it can be triggered by sending a crafted HTTP request to the server's file download endpoint. The scope of affected systems includes any deployment of parse-server versions within the vulnerable ranges, which may be used in various industries for backend services supporting mobile and web applications.

For European organizations using parse-server as part of their backend infrastructure, this vulnerability poses a risk of service disruption through Denial of Service attacks. Attackers can exploit the flaw by sending malformed file download requests with invalid byte ranges, causing the server to crash and become unavailable. This can lead to downtime, loss of availability of critical applications, and potential reputational damage. Industries relying on parse-server for customer-facing applications, internal tools, or IoT device management could experience operational interruptions. While the vulnerability does not directly compromise confidentiality or integrity, the loss of availability can impact business continuity and service level agreements. Additionally, repeated exploitation attempts could increase operational costs due to incident response and recovery efforts. Given parse-server's open-source nature and deployment flexibility, organizations using customized or self-hosted instances may be particularly vulnerable if they have not applied the patches. The lack of known exploits in the wild suggests limited active targeting, but the ease of triggering the crash without authentication means opportunistic attackers could leverage this vulnerability.

European organizations should prioritize upgrading parse-server instances to version 4.10.17 or later, or 5.2.8 or later on the 5.x branch, to remediate the vulnerability. Since no workarounds exist, patching is the only effective mitigation. Organizations should audit their infrastructure to identify all parse-server deployments, including development, staging, and production environments, to ensure comprehensive coverage. Implementing network-level protections such as Web Application Firewalls (WAFs) can help detect and block malformed HTTP requests with suspicious byte range headers, adding a layer of defense against exploitation attempts. Monitoring server logs for repeated crashes or unusual file download requests can provide early indicators of attempted exploitation. Additionally, rate limiting file download requests and enforcing strict input validation at the application or proxy level can reduce the attack surface. Organizations should also incorporate this vulnerability into their incident response plans and conduct regular vulnerability assessments to detect outdated parse-server versions. Finally, engaging with the parse-community project for updates and security advisories is recommended to stay informed about future patches or related vulnerabilities.