CVE-2026-81520— MongoDB Connector for BI Unbounded Authentication Negotiation Leading to Connection Exhaustion
Quick assessment
Affected
MongoDB BI Connector
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
MongoDB BI Connector是美国MongoDB公司的一个连接商业智能工具与数据库的桥梁。 MongoDB BI Connector 2.14.31之前版本存在资源管理错误漏洞，该漏洞源于身份验证协商循环没有总体时间限制且从客户端读取没有截止时间，可能导致未经身份验证的网络客户端启动基于SASL的登录交换后拒绝完成，从而无限期保持身份验证会话并消耗连接容量，造成拒绝服务。
Possible ATT&CK Techniques 1 AI
T1027.004 · Compile After DeliveryAffected Version Matrix 1
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| MongoDB | BI Connector | < 2.14.31 |
affected |
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I. Basic Information for CVE-2026-81520
Vulnerability Information
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Vulnerability Title
MongoDB Connector for BI Unbounded Authentication Negotiation Leading to Connection Exhaustion
Source: CVE Program / CVE List V5
Vulnerability Description
A network-reachable client that has not yet authenticated can hold a MongoDB Connector for BI authentication session open indefinitely by beginning a SASL-based login exchange and then declining to complete it. Because the negotiation loop had no overall time bound and the read from the client had no deadline, each such session retains a worker, a client connection slot, and its associated backend database connections until the process is restarted. Repeated use of this behavior can consume the configured connection capacity and prevent legitimate users from establishing new sessions.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
远程资源无超时同步访问
Source: CVE Program / CVE List V5
Vulnerability Title
MongoDB BI Connector 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
MongoDB BI Connector是美国MongoDB公司的一个连接商业智能工具与数据库的桥梁。 MongoDB BI Connector 2.14.31之前版本存在资源管理错误漏洞，该漏洞源于身份验证协商循环没有总体时间限制且从客户端读取没有截止时间，可能导致未经身份验证的网络客户端启动基于SASL的登录交换后拒绝完成，从而无限期保持身份验证会话并消耗连接容量，造成拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| MongoDB | BI Connector | 0 ~ 2.14.31 | - |
|
II. Public POCs for CVE-2026-81520
| # | POC Description | Source Link | Shenlong Link |
|---|
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Same Patch Batch · MongoDB · 2026-08-28 · 11 CVEs total
| CVE-2026-81532 | 8.8 HIGH | BI Connector ODBC Driver Improper Bounds Checking on Cursor Name Leading to Memory Corrupt |
| CVE-2026-77586 | 8.0 HIGH | MongoDB Connector for BI Unescaped Object Names in Generated SHOW CREATE Output |
| CVE-2026-81490 | 7.7 HIGH | MongoDB Connector for BI Improper Error Handling During Schema Sampling May Cause Loss of |
| CVE-2026-81517 | 7.5 HIGH | MongoDB Connector for BI Improper Error Handling of Log Write Failures May Cause Loss of S |
| CVE-2026-81518 | 7.5 HIGH | BI Connector Optional Client Certificate Verification Allows Unauthenticated Connections |
| CVE-2026-81533 | 7.1 HIGH | MongoDB BI Connector ODBC Driver Memory-Safety Issue When Parsing Oversized LIMIT Values |
| CVE-2026-76798 | 6.3 MEDIUM | MongoSQL Transition Readiness Tool Improper Output Encoding in Generated HTML Reports |
| CVE-2026-76797 | 6.3 MEDIUM | MongoSQL Transition Readiness Tool Improper Neutralization of Formula Elements in Generate |
| CVE-2026-77184 | 5.2 MEDIUM | MongoDB Connector for BI Incomplete Escaping of Stored Metadata in Generated SHOW CREATE O |
| CVE-2026-76794 | 4.6 MEDIUM | MongoDB BI Connector Transition Readiness Report Improper HTML Encoding When Processing Da |
IV. Related Vulnerabilities
Same product: BI Connector
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CVE-2026-81518
BI Connector Optional Client Certificate Verification Allows -
CVE-2026-81517
MongoDB Connector for BI Improper Error Handling of Log Writ -
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MongoDB Connector for BI Improper Error Handling During Sche -
CVE-2026-77586
MongoDB Connector for BI Unescaped Object Names in Generated -
CVE-2026-77184
MongoDB Connector for BI Incomplete Escaping of Stored Metad
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V. Comments for CVE-2026-81520
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