Apollo Federation’s query plan execution performs incomplete sanitization of keys used in field aliases, variable names, and JSON responses, which allows a malicious actor to target JavaScript’s prototype‑inheritable properties and pollute Object.prototype. Pollution of the prototype can alter the behaviour of subsequent requests processed by the gateway. The advisory does not state that this leads to remote code execution; therefore the impact is limited to potential behaviour changes and, based on the description, it is inferred that a denial‑of‑service or other unintended functionality could result, but such effects are not confirmed by the vendor.

The vulnerability exposes @apollo:federation‑internals, @apollo:gateway, and @apollo:query‑planner. All releases prior to 2.9.6, 2.10.5, 2.11.6, 2.12.3, and 2.13.2 are affected as explicitly identified in the advisory’s version table.

The CVSS score of 9.9 classifies the flaw as critical, indicating a high potential for severe impact. The EPSS score is reported as less than 1%, suggesting a low current exploitation probability, and the vulnerability is not listed in the CISA KEV catalog. Exploitation can occur by a malicious client crafting GraphQL operations with field aliases or variable names that target prototype‑inheritable properties, or by a compromised subgraph sending specially crafted JSON response payloads. Based on the description, it is inferred that no special privileges are required; thus an authenticated or unauthenticated user could potentially attempt exploitation.