CVE-2026-81528

NoSQL injection via array replacement bypassing update shape validation in driver write path

Published Aug 27, 2026 CVSS 4.0 · 5.3 Medium EPSS < 1% KEV · Not listed
Description
A MongoDB C# driver document-replacement code path omits the element-name/shape validation that the equivalent write paths apply, so a value supplied as a replacement is forwarded to the server without neutralization of query-language special elements. An application that passes untrusted, loosely-typed input as a replacement value therefore allows that input to be interpreted by the database as update logic rather than as data, executing under the application's own database credentials. Applications using strongly-typed document mappings are not affected.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', '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 MongoDB C# driver document-replacement code path omits the element-name/shape validation that the equivalent write paths apply, so a value supplied as a replacement is forwarded to the server without neutralization of query-language special elements. An application that passes untrusted, loosely-typed input as a replacement value therefore allows that input to be interpreted by the database as update logic rather than as data, executing under the application's own database credentials. Applications using strongly-typed document mappings are not affected.
Title NoSQL injection via array replacement bypassing update shape validation in driver write path
Weaknesses CWE-943
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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, 3:45 PM
Reserved
Aug 26, 2026, 10:14 PM
Status
Analyzed
Published
Aug 27, 2026, 8:18 PM
Modified
Sep 29, 2026, 7:16 PM