CVE-2026-81527

NoSQL injection via unquoted constant GroupBy keys in LINQ pipeline translation

Published Aug 27, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

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History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mongodb c\# Driver
CPEs cpe:2.3:a:mongodb:c\#_driver:*:*:*:*:*:mongodb:*:*
Vendors & Products Mongodb c\# Driver
Type Values Removed Values Added
First Time appeared Mongodb
Mongodb c# Driver
Vendors & Products Mongodb
Mongodb c# Driver
Type Values Removed Values Added
Description 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.
Title NoSQL injection via unquoted constant GroupBy keys in LINQ pipeline translation
Weaknesses CWE-943
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mongodb
Published
Updated
Aug 28, 2026, 3:46 PM
Reserved
Aug 26, 2026, 10:14 PM
Status
Analyzed
Published
Aug 27, 2026, 8:18 PM
Modified
Sep 29, 2026, 7:16 PM