CVE-2026-81528Network attack vectorHinoki check available

NoSQL injection via unvalidated array replacements

Published Aug 27, 2026 · Updated Aug 27, 2026

NoSQL injection in MongoDB .NET/C# Driver 2.9.0 through 3.11.0 allows remote authenticated users to alter database data via replacement values. The document-replacement write path forwards array values without the element-name and shape validation used by equivalent paths, so special elements become update logic. Exposure requires untrusted, loosely typed replacement input; strongly typed mappings are unaffected, and database actions run with the application's credentials.

CVSS severity5.3
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

NoSQL injection in MongoDB .NET/C# Driver 2.9.0 through 3.11.0 allows remote authenticated users to alter database data via replacement values. The document-replacement write path forwards array values without the element-name and shape validation used by equivalent paths, so special elements become update logic. Exposure requires untrusted, loosely typed replacement input; strongly typed mappings are unaffected, and database actions run with the application's credentials.

The record

CVE
CVE-2026-81528
Published
Aug 27, 2026
Updated
Aug 27, 2026
Vendor
MongoDB
Product
MongoDB .NET/C# Driver
Classifications
CWE-943
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.9.0 <3.11.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

MongoDB · MongoDB .NET/C# Driverversion=2.9.0 <3.11.1

Published CVSS scores

5.4MongoDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
5.3MongoDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-943Improper Neutralization of Special Elements in Data Query Logic

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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