Medium severity · published Aug 11, 2026
CVE-2026-18703
Improper Enforcement of Authentication Mechanism Restrictions in MongoDB Server Allows Use of Disabled Authentication Method
4.2
CVSS
0.1%
EPSS
No
On KEV
Description
An issue in MongoDB Server could allow a party with a valid client certificate and a corresponding user account to authenticate using a certificate-based authentication method, even when an administrator has configured the server to restrict authentication to other mechanisms. This could allow authentication through a method the administrator intended to disable.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 4% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MO
MongoDB · MongoDB
8.3.0 before 8.3.8 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-18703
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-18703
Vendor Advisory
https://jira.mongodb.org/browse/SERVER-127863
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-2025-3085
A MongoDB server under specific conditions running on Linux with TLS and CRL revocation status checking enabled, fails to check the revocation status of the intermediate…
9.8
CVE-2024-8654
MongoDB Server may access non-initialized region of memory leading to unexpected behaviour