CVE-2026-114646 MongoDB CVE debrief

Who should care

Defenders responsible for MongoDB C# Driver deployments, especially those handling externally supplied binary data, should assess exposure and prioritize verification and remediation efforts.

Why it matters

Defenders should prioritize verifying the versions of MongoDB C# Driver in use and assessing the exposure of applications that utilize this driver, especially those handling externally supplied binary data, to prevent potential unauthorized modification of stored data and disclosure of data outside the intended scope.

• Potential unauthorized modification of stored data
• Potential disclosure of data outside the intended scope of the application's request
• Need to verify versions of MongoDB C# Driver in use
• Need to assess exposure of applications handling externally supplied binary data

Technical summary

The MongoDB C# Driver does not verify the size quantity declared in externally supplied binary data and copies it onto the wire unchanged, allowing an unauthenticated party to cause additional elements to be inserted into or existing elements to be removed from the database command. This can result in unauthorized modification of stored data and disclosure of data outside the intended scope of the application's request, bounded by the database privileges the application itself holds. The driver does not perform adequate validation on the BSON length prefix, which can lead to security issues when dealing with externally supplied binary data.

Defensive priority

Defenders should prioritize verifying the versions of MongoDB C# Driver in use and assessing the exposure of applications that utilize this driver, especially those handling externally supplied binary data.

Recommended defensive actions

• Verify the version of MongoDB C# Driver in use and upgrade to version 3.13.0 or later if necessary.
• Assess the exposure of applications that utilize this driver, especially those handling externally supplied binary data.
• Implement additional validation and sanitization of externally supplied binary data to prevent similar attacks.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE Program record and NVD vulnerability detail provide official information about the vulnerability. The source item and supplemental sources offer additional context and references. Defenders should verify the versions of MongoDB C# Driver in use and assess the exposure of applications that utilize this driver, especially those handling externally supplied binary data. This verification process involves checking the driver's version and ensuring that it is not vulnerable to the described data-validation flaw. Additionally, it is

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.