CVE-2026-18693: Out-of-Bounds Read/Write in MongoDB Timeseries Bucket Handling Leads to Denial of Service and Potential Memory Disclosure

An issue in MongoDB Server's handling of timeseries collections could allow an authenticated user with write privileges to cause an internal data structure to become inconsistent through certain document insertions. A subsequent insert into the affected bucket could then result in the server accessing memory outside its intended bounds, potentially causing a server crash (denial of service), exposure of limited memory contents, or memory corruption.