CVE-2026-81529 HIGH

CVE-2026-81529: Connection-option injection via unescaped settings in the canonical MongoDB URL builder

Vendor Mongodb
Product C# Driver
Weakness CWE-88
Published August 27, 2026
Last update August 28, 2026

CVSS base score

7.1/10
Attack vector Network
Attack complexity High
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N

What the vulnerability does

01Description

Improper neutralization of delimiters in connection-URL construction allows connection-option injection in the MongoDB C# Driver. When an application passes untrusted text into the driver's connection-URL builder and round-trips the builder back into a client configuration, the untrusted text is serialized without neutralizing the URL/option delimiters and is then re-parsed as authoritative connection options. A low-privileged user of such an application can thereby introduce or suppress security-relevant connection settings.

Key dates

02Disclosure timeline

August 27, 2026 CVE published
August 28, 2026 Record updated