# CVE-2026-9748: $_internalConvertBucketIndexStats may crash the mongod server when working on no timeseries input

CVE-2026-9748 is fixed in MongoDB on 1 platform by MongoDB 8.3.3 (version 8.3.3), released May 28, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-9748
- Priority: High
- CVSS: 7.1
- EPSS: 0.0032
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 9, 2026
- Weakness: CWE-617: Reachable assertion
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-9748

## Description

The $_internalConvertBucketIndexStats stage used PauseExecution as a way to signal "skip this document" when an index stats conversion failed. But PauseExecution is not a general purpose skip mechanism, but rather a TeeBuffer-internal signal used solely by $facet to coordinate its sub-pipelines. When this stage is placed before $facet in a pipeline, TeeBuffer receives the unexpected PauseExecution from upstream and hits a hard invariant assertion, crashing mongod.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | MongoDB | 8.3.3 | [MongoDB 8.3.3](https://patchblox.com/security/data/fix/windows-app/mongodb.server-8.3.3.md) | May 28, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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