CVE-2026-9749 — Using MaxKey() may crash the server
This issue can occur when running an aggregation pipeline that uses the internal $exchange stage configured with key-range partitioning and order-preserving delivery. If a singl…
Published: 2026-06-09 · CVSS: 7.1 · CVSS 4.0
This issue can occur when running an aggregation pipeline that uses the internal $exchange stage configured with key-range partitioning and order-preserving delivery. If a single key range produces enough documents to fill its exchange buffer (that is, many results are routed to the same consumer), the server reaches the code path where a full per-consumer buffer is detected but the internal "high watermark" for that key range is not updated as intended.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7