Connection-option injection via unescaped settings in the canonical MongoDB URL builder

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-81529
StatePUBLISHED
Assignermongodb
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-27 20:18:51 UTC
Updated2026-08-27 20:18:51 UTC
DescriptionImproper neutralization of delimiters in connection-URL construction allows connection-option injection in the MongoDB C# Driver. When an application passes untrusted text into the driver's connection-URL builder and round-trips the builder back into a client configuration, the untrusted text is serialized without neutralizing the URL/option delimiters and is then re-parsed as authoritative connection options. A low-privileged user of such an application can thereby introduce or suppress security-relevant connection settings.

Risk And Classification

Primary CVSS: v4.0 7.1 HIGH from [email protected]

CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-88 | CWE-88 CWE-88: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary7.1HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N/E:X/C...
4.0CNACVSS7.1HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N
3.1[email protected]Secondary7.1HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N
3.1CNACVSS7.1HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
High
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Confidentiality
High
Integrity
Low
Availability
None
Sub Conf.
High
Sub Integrity
Low
Sub Availability
None

CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA MongoDB C Driver affected 3.5.0 3.11.1 semver Not specified

References

ReferenceSourceLinkTags
www.nuget.org/packages/MongoDB.Driver/3.11.1 [email protected] www.nuget.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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