CVE-2026-81527Network attack vector

NoSQL injection via unsafe LINQ constant translation

Published Aug 27, 2026 · Updated Aug 27, 2026

NoSQL injection in MongoDB C# Driver 2.14.0 through 3.11.0 allows remote attackers to read or alter query results via crafted values. The GroupBy pipeline translator emits constant keys without quoting, equality-filter simplification preserves dollar-keyed documents as query expressions, and constant arrays and documents pass dollar-prefixed values without escaping. Exploitation requires an application to incorporate attacker-controlled values into an affected LINQ query; database execution can expose unintended data or alter filtering, but no availability impact is reported.

CVSS severity6.9
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NoSQL injection in MongoDB C# Driver 2.14.0 through 3.11.0 allows remote attackers to read or alter query results via crafted values. The GroupBy pipeline translator emits constant keys without quoting, equality-filter simplification preserves dollar-keyed documents as query expressions, and constant arrays and documents pass dollar-prefixed values without escaping. Exploitation requires an application to incorporate attacker-controlled values into an affected LINQ query; database execution can expose unintended data or alter filtering, but no availability impact is reported.

The record

CVE
CVE-2026-81527
Published
Aug 27, 2026
Updated
Aug 27, 2026
Vendor
MongoDB
Product
MongoDB C++ Driver
Classifications
CWE-943, T1190
Attack vector
network
Privileges
unauthenticated

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=2.14.0 <3.11.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

MongoDB · MongoDB C++ Driverversion=2.14.0 <3.11.1

Published CVSS scores

6.5MongoDB, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
6.9MongoDB, Inc.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

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-943Improper Neutralization of Special Elements in Data Query Logic
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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