High severity · published Aug 28, 2026
CVE-2026-81520
MongoDB Connector for BI Unbounded Authentication Negotiation Leading to Connection Exhaustion
7.5
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MO
MongoDB · MongoDB
before 2.14.31 · source: vendor
BC
BI Connector · Mongodb
before 2.14.31 · source: NVD
Affected product
MO
MongoDB
MongoDB
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