High severity · published Aug 28, 2026
CVE-2026-81518
BI Connector Optional Client Certificate Verification Allows Unauthenticated Connections
7.5
CVSS
0.3%
EPSS
No
On KEV
Description
When mongosqld is configured with a client certificate authority file, the listener requests a client certificate during the TLS handshake but does not require one, so a client that presents no certificate is still accepted. In deployments that rely on client certificates as the sole means of identifying users, a remote party with network access to the listener can therefore establish a session and read the MongoDB data exposed through the connector.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 17% 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
More from MongoDB
9.9
CVE-2019-10758
MongoDB mongo-express Remote Code Execution Vulnerability
7.5
CVE-2025-14847
Zlib compressed protocol header length confusion may allow memory read
9.8
CVE-2026-19001
MongoDB BI Connector ODBC driver may write outside an allocated buffer when handling oversized catalog object names
9.8
CVE-2025-40906
BSON::XS versions 0.8.4 and earlier for Perl includes a bundled libbson 1.1.7, which has several vulnerabilities
9.8
CVE-2025-3085
MongoDB Server running on Linux may allow unexpected connections where intermediate certificates are revoked