CVE-2026-9749

HIGHCVSS 7.1/10EPSS 0.27%

Last modified

CVE-2026-9749 is a high-severity vulnerability rated 7.1/10 on the CVSS scale. 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.. EPSS estimates a 0.27% chance of exploitation in the next 30 days.

Description

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.

Metrics

Weakness Enumeration

Affected Software

VendorProductVersions
MongodbMongodb>= 7.0.0, < 7.0.35
MongodbMongodb>= 8.0.0, < 8.0.24
MongodbMongodb>= 8.2.0, < 8.2.10
MongodbMongodb>= 8.3.0, < 8.3.3

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-9749?
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.
How severe is CVE-2026-9749?
CVE-2026-9749 has a CVSS score of 7.1/10 (HIGH severity). The EPSS model estimates a 0.27% probability of exploitation in the next 30 days.
How do I fix CVE-2026-9749?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST