What’s Vulnerable › Vulnerabilities

CVE-2026-96746: Heap buffer overflow via mid-scan command list growth in client topology monitoring

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-24 · updated 2026-09-24
• Weakness: CWE-787

Description

An out-of-bounds write in the connection-monitoring logic of the MongoDB C Driver may allow an unauthenticated party who controls name resolution and the responses of the hosts named in a client's connection string to write beyond the end of a heap buffer. This may cause the application using the driver to terminate unexpectedly.

Affected products

• MongoDB C# Driver: before 1.30.12; from 2.0.0 before 2.5.5 — fixed in 1.30.12, 2.5.5

How to fix

Upgrade to a fixed version: MongoDB C# Driver 1.30.12, 2.5.5. Check the vendor advisory for mitigations.

References

• https://github.com/mongodb/mongo-c-driver/releases/tag/1.30.12
• https://github.com/mongodb/mongo-c-driver/releases/tag/2.5.5
• https://github.com/mongodb/mongo-c-driver/security/advisories/GHSA-frjf-h5jg-4v46

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