A Windows Print Spooler vulnerability that Microsoft patched in June 2021, presents a much greater danger than initially thought: researchers have proved that it can be exploited to achieve remote code execution. The vulnerability was initially classed as low severity vulnerability, allowing local privilege elevation, and was patched on June 2021 Patch Tuesday. But on June 21, 2021, Microsoft changed the classification because it was discovered that the flaw allows for remote. code execution (RCE) and it was re-classified as critical.
Source: https://www.helpnetsecurity.com/2021/06/30/poc-cve-2021-1675/