CVE-2026-81520: CWE-1088: Synchronous Access of Remote Resource without Timeout in MongoDB BI Connector
Description
CVE-2026-81520 is a vulnerability in the MongoDB BI Connector where an unauthenticated network client can indefinitely hold an authentication session open by starting but not completing a SASL login exchange. This lack of timeout or read deadline allows the session to retain resources such as a worker, client connection slot, and backend database connections until the process is restarted. Repeated exploitation can exhaust connection capacity, blocking legitimate users from establishing new sessions.
CVSS v4.0
Score 8.7high
Affected software
MongoDB
BI Connector
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The MongoDB BI Connector contains a vulnerability (CWE-1088) involving synchronous access of a remote resource without a timeout. An unauthenticated client can initiate a SASL-based login exchange and then decline to complete it, causing the authentication session to remain open indefinitely. Because the negotiation loop has no overall time bound and no read deadline, each such session consumes server resources (worker, connection slots, backend connections) until the server process is restarted. This can lead to denial of service by exhausting the configured connection capacity.
Potential Impact
An attacker can cause a denial of service by consuming all available connection slots and backend database connections through incomplete authentication sessions. This prevents legitimate users from establishing new sessions until the MongoDB BI Connector process is restarted. No privilege escalation or data compromise is described.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider monitoring connection usage and restarting the MongoDB BI Connector process to recover from resource exhaustion. No official fix or temporary workaround is currently documented.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mongodb
- Date Reserved
- 2026-08-26T22:10:21.151Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a9206c9acd9273b4963cf5f
Added to database: 08/28/2026, 22:08:09 UTC
Last enriched: 09/07/2026, 15:28:15 UTC
Last updated: 10/13/2026, 18:48:24 UTC
Views: 98
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