CVE-2023-28104: 
PHP vulnerability analysis and mitigation

CVE-2023-28104 affects the silverstripe/graphql package, which serves Silverstripe data as GraphQL representations. The vulnerability was discovered and disclosed on March 16, 2023, affecting versions 4.2.2 and 4.1.1. The issue allows attackers to execute a denial of service attack against websites with publicly exposed GraphQL endpoints, particularly impacting those with large or complex GraphQL schemas (GitHub Advisory).

The vulnerability has been assigned a CVSS v3.1 base score of 7.5 (High), with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. This indicates that the vulnerability can be exploited remotely (Network), requires low attack complexity, needs no privileges or user interaction, and primarily impacts system availability. The vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling) (NVD).

The primary impact of this vulnerability is on system availability through denial of service attacks. The attack is particularly effective against websites with large or complex GraphQL schemas. For websites that don't expose a public-facing GraphQL schema, a user account would be required to trigger the DoS attack. Sites hosted behind CDNs like Imperva or CloudFlare may have additional mitigation against this vulnerability (GitHub Advisory).

Users should upgrade to silverstripe/graphql version 4.2.3 or 4.1.2 to address this vulnerability. Additional mitigation can be achieved by placing the website behind a content delivery network (CDN) such as Imperva or CloudFlare, and ensuring GraphQL endpoints are not publicly exposed without authentication (GitHub Advisory).