CVE-2026-96299: CWE-617: Reachable Assertion in MongoDB MongoDB Server
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.
CVSS v4.0
Score 7.1high
Affected software
MongoDB
MongoDB Server
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves the lack of resource usage limits in the match expression evaluator of MongoDB Server. Internal schema validation operators, which should be restricted to server use, are accepted in user queries. When nested and applied to array-containing documents, the server evaluates all combinations of array elements without throttling, leading to excessive memory consumption. This can cause the mongod process to exhaust memory and crash. The vulnerability affects MongoDB Server versions >=8.3.0 <8.3.13 and >=9.0 <9.0.4 and can be exploited by authenticated users with read-only privileges via aggregation queries.
Potential Impact
An attacker with authenticated read-only access can cause the MongoDB server process to consume excessive memory and terminate unexpectedly. This results in a denial of service condition affecting availability. There is no indication of privilege escalation or data compromise from the provided information.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict access to trusted users and monitor query patterns that may involve nested internal schema validation operators in aggregation queries. Avoid running untrusted aggregation queries that could trigger this behavior.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mongodb
- Date Reserved
- 2026-09-22T22:29:05.501Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ace52f92cdf04f65680e4fb
Added to database: 10/13/2026, 15:49:13 UTC
Last enriched: 10/13/2026, 16:03:20 UTC
Last updated: 10/13/2026, 16:49:17 UTC
Views: 4
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