CVE-2026-9748: CWE-617 Reachable assertion in MongoDB MongoDB Server
CVE-2026-9748 is a high-severity vulnerability in MongoDB Server involving a reachable assertion failure. The issue arises from the $_internalConvertBucketIndexStats stage using PauseExecution incorrectly as a skip signal, which is intended only for internal coordination by $facet. When this stage precedes $facet in a pipeline, it causes an unexpected PauseExecution signal that triggers a hard invariant assertion failure, crashing the mongod process.
AI Analysis
Technical Summary
This vulnerability in MongoDB Server occurs because the $_internalConvertBucketIndexStats stage uses PauseExecution to signal skipping a document when index stats conversion fails. However, PauseExecution is designed solely as an internal signal for $facet's TeeBuffer coordination. If $_internalConvertBucketIndexStats is placed before $facet in an aggregation pipeline, TeeBuffer receives an unexpected PauseExecution signal from upstream, leading to a reachable assertion failure that crashes the mongod server process. This is classified under CWE-617 (Reachable Assertion).
Potential Impact
Successful exploitation causes the mongod process to crash due to a hard invariant assertion failure. This results in denial of service (DoS) for the affected MongoDB server instance. There is no indication of data corruption or privilege escalation from the provided information.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary workaround is indicated in the provided data. Until a patch is available, avoid constructing aggregation pipelines where $_internalConvertBucketIndexStats precedes $facet to prevent triggering the assertion failure.
CVE-2026-9748: CWE-617 Reachable assertion in MongoDB MongoDB Server
Description
CVE-2026-9748 is a high-severity vulnerability in MongoDB Server involving a reachable assertion failure. The issue arises from the $_internalConvertBucketIndexStats stage using PauseExecution incorrectly as a skip signal, which is intended only for internal coordination by $facet. When this stage precedes $facet in a pipeline, it causes an unexpected PauseExecution signal that triggers a hard invariant assertion failure, crashing the mongod process.
CVSS v4.0
Score 7.1high
Affected software
pkg:github/mongodb/mongoRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability in MongoDB Server occurs because the $_internalConvertBucketIndexStats stage uses PauseExecution to signal skipping a document when index stats conversion fails. However, PauseExecution is designed solely as an internal signal for $facet's TeeBuffer coordination. If $_internalConvertBucketIndexStats is placed before $facet in an aggregation pipeline, TeeBuffer receives an unexpected PauseExecution signal from upstream, leading to a reachable assertion failure that crashes the mongod server process. This is classified under CWE-617 (Reachable Assertion).
Potential Impact
Successful exploitation causes the mongod process to crash due to a hard invariant assertion failure. This results in denial of service (DoS) for the affected MongoDB server instance. There is no indication of data corruption or privilege escalation from the provided information.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary workaround is indicated in the provided data. Until a patch is available, avoid constructing aggregation pipelines where $_internalConvertBucketIndexStats precedes $facet to prevent triggering the assertion failure.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mongodb
- Date Reserved
- 2026-05-27T17:47:07.609Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a2892f48dd33fbd858e3b44
Added to database: 06/09/2026, 22:25:56 UTC
Last enriched: 06/17/2026, 09:14:39 UTC
Last updated: 07/31/2026, 19:23:00 UTC
Views: 72
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