Description
A security issue was discovered in MongoDB mongos (the sharded cluster router) where an authenticated user with readWrite privileges could crash the mongos process by crafting a specially formed aggregation pipeline. The issue leverages an internal aggregation stage that lacks proper authorization checks despite being intended for internal use, allowing a subsequent stage to be forced to execute on the router under conditions it was not designed to handle. This results in an unhandled fatal error that causes the mongos process to immediately abort, resulting in denial of service for all clients routed through the affected mongos instance.
Published: 2026-10-13
Score: 7.1 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Tue, 13 Oct 2026 17:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-770
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 13 Oct 2026 17:00:00 +0000

Type Values Removed Values Added
First Time appeared Mongodb
Mongodb mongodb Server
Vendors & Products Mongodb
Mongodb mongodb Server

Tue, 13 Oct 2026 16:45:00 +0000

Type Values Removed Values Added
Description Missing limits on resource use in the match expression evaluator of MongoDB Server can cause the server to consume excessive memory. Internal schema validation operators that are meant only for server use are accepted in user-supplied query filters. When these operators are nested and applied to documents that contain arrays, the server evaluates every combination of array elements without a sufficient limit on the resources used. This can cause memory use to grow until the mongod process runs out of memory and terminates. The behavior can occur when an authenticated user with read-only privileges runs an aggregation query that nests these operators. A security issue was discovered in MongoDB mongos (the sharded cluster router) where an authenticated user with readWrite privileges could crash the mongos process by crafting a specially formed aggregation pipeline. The issue leverages an internal aggregation stage that lacks proper authorization checks despite being intended for internal use, allowing a subsequent stage to be forced to execute on the router under conditions it was not designed to handle. This results in an unhandled fatal error that causes the mongos process to immediately abort, resulting in denial of service for all clients routed through the affected mongos instance.
Title MongoDB Nested `$_internalSchemaAllElemMatchFromIndex` Cross-Product MatchExpression OOM Missing Authorization Check on Internal Aggregation Stage in MongoDB Server mongos Leads to Denial of Service
Weaknesses CWE-617

Tue, 13 Oct 2026 15:45:00 +0000

Type Values Removed Values Added
Description Missing limits on resource use in the match expression evaluator of MongoDB Server can cause the server to consume excessive memory. Internal schema validation operators that are meant only for server use are accepted in user-supplied query filters. When these operators are nested and applied to documents that contain arrays, the server evaluates every combination of array elements without a sufficient limit on the resources used. This can cause memory use to grow until the mongod process runs out of memory and terminates. The behavior can occur when an authenticated user with read-only privileges runs an aggregation query that nests these operators.
Title MongoDB Nested `$_internalSchemaAllElemMatchFromIndex` Cross-Product MatchExpression OOM
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 7.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Subscriptions

Mongodb Mongodb Server
cve-icon MITRE

Status: PUBLISHED

Assigner: mongodb

Published:

Updated: 2026-10-13T16:31:19.871Z

Reserved: 2026-09-22T22:29:05.501Z

Link: CVE-2026-96299

cve-icon Vulnrichment

Updated: 2026-10-13T16:15:34.989Z

cve-icon NVD

Status : Received

Published: 2026-10-13T16:17:24.323

Modified: 2026-10-13T17:17:49.470

Link: CVE-2026-96299

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-13T16:45:19Z

Weaknesses