MongoDB C# Driver up to 3.11.0 Query Translation injection

Summaryinfo

A vulnerability, which was classified as critical, has been found in MongoDB C# Driver up to 3.11.0. Affected by this issue is some unknown functionality of the component Query Translation. This manipulation causes injection. This vulnerability is tracked as CVE-2026-81527. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability classified as critical was found in MongoDB C# Driver up to 3.11.0. Affected by this vulnerability is an unknown functionality of the component Query Translation. The manipulation with an unknown input leads to a injection vulnerability. The CWE definition for the vulnerability is CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

A NoSQL/expression injection weakness exists in the LINQ-to-aggregation query translation layer of the MongoDB C# Driver, in both aggregation expression and query filter translation. When application-supplied values are embedded in certain query constructs, special elements contained within those values are not properly escaped before the resulting query is transmitted to the database, so portions of the value may be interpreted by the database as query logic rather than as data. A user able to supply values that an application incorporates into an affected query may thereby cause unintended data to be returned or query results to be altered.

The advisory is shared at nuget.org. This vulnerability is known as CVE-2026-81527 since 08/27/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1055 for this issue.

Upgrading to version 3.11.1 eliminates this vulnerability.

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Productinfo

Type

• Database Software

Vendor

• MongoDB

Name

• C# Driver

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10
• 3.11.0

License

• open-source

CPE 2.3info

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CPE 2.2info

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