CVE-2026-9749

Summary

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.

Affected Software

VendorProductVersion RangeStatus
MongoDBMongoDB Server8.3.0 < 8.3.3affected
MongoDBMongoDB Server8.2.0 < 8.2.10affected
MongoDBMongoDB Server8.0.0 < 8.0.24affected
MongoDBMongoDB Server7.0.0 < 7.0.35affected

Weaknesses

  • CWE-617: CWE-617 Reachable assertion

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References