CVE-2021-29116
A stored Cross Site Scripting (XSS) vulnerability in Esri ArcGIS Server feature services versions 10.8.1 and 10.9 (only) feature services may allow a remote, unauthenticated attacker to pass and store malicious strings via crafted queries which when accessed could potentially execute arbitrary JavaScript code in the user’s browser.
Source: CVE-2021-29116