Parse Server’s rate limiting middleware is applied only at the Express middleware layer, but the /batch endpoint processes sub‑requests directly through the Promise router, bypassing that layer. An attacker can therefore bundle multiple requests that would normally be rate‑limited into a single batch request, circumventing the configured limits. This improper restriction of resources flaw can cause denial of service by exhausting CPU, memory or network bandwidth. The vulnerability does not provide direct code execution or data exposure.

All unpatched deployments of Parse Server older than 9.5.2‑alpha.10 and 8.6.23, including every alpha release from 9.5.2‑alpha.1 through alpha.9, are affected. The issue applies to every instance of the open source Parse Server that runs on Node.js and uses the built‑in rate limiting feature.

The CVSS score of 6.9 indicates moderate severity. An EPSS of less than 1% signals a low but non‑zero likelihood of exploitation in the near term, and the vulnerability is not listed in the CISA known exploited vulnerabilities catalog, meaning no active publicly known exploits have been reported. The flaw can be exploited by any client that has permission to submit batch requests, allowing an attacker to flood the server with a high volume of batched requests and potentially bring the service down. The risk is amplified in high‑traffic or publicly exposed environments.