CVE-2026-93393: Memory Corruption (CVSS 8.1)

Description

A heap-based buffer overflow exists in the TLS transport layer of the MongoDB C Driver when built with the Windows platform TLS backend. A remote endpoint that the client connects to can cause the driver to write uncontrolled data outside the bounds of a heap allocation while processing incoming encrypted traffic after the TLS handshake completes. No authentication or user interaction is required, because the affected processing occurs before any application-level authentication completes. Triggering this issue may lead to memory corruption in the client process, disclosure of adjacent heap memory, or termination of the process.

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CVSS v3.1 Score

8.1

HIGH

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

EPSS — Exploit Prediction

0.0047

Probability of exploitation

0.39%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

References

Other References

https://jira.mongodb.org/browse/CDRIVER-6417

Frequently Asked Questions

What is CVE-2026-93393? +

A heap-based buffer overflow exists in the TLS transport layer of the MongoDB C Driver when built with the Windows platform TLS backend. A remote endpoint that the client connects to can cause the driver to write uncontrolled data outside the bounds of a heap allocation while processing incoming encrypted traffic after the TLS handshake completes. No authentication or user interaction is required, because the affected processing occurs before any application-level authentication completes. Triggering this issue may lead to memory corruption in the client process, disclosure of adjacent heap memory, or termination of the process. It has a CVSS v3.1 base score of 8.1 (HIGH).

How severe is CVE-2026-93393? +

CVE-2026-93393 has a CVSS v3.1 score of 8.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0047, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-93393? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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