Vulnerability · Published Sep 17, 2026 · Assigned by mongodb
CVE-2026-93393Heap overflow via oversized decrypted TLS record sequence in Windows Secure Channel stream
High 8.1
In plain English
A high-severity out-of-bounds write in C Driver from MongoDB Inc.. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | mongo-c-driver | 1.30.14-r0 | ALPINE-CVE-2026-93393 |
| Debian:12 | mongo-c-driver | no fix listed | DEBIAN-CVE-2026-93393 |
| Debian:13 | mongo-c-driver | no fix listed | DEBIAN-CVE-2026-93393 |
| Debian:14 | mongo-c-driver | 2.5.5-1 | DEBIAN-CVE-2026-93393 |
| Ubuntu:26.04:LTS | mongo-c-driver | no fix listed | UBUNTU-CVE-2026-93393 |
| Ubuntu:26.10 | mongo-c-driver | no fix listed | UBUNTU-CVE-2026-93393 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| MongoDB Inc. | C Driver | 2.4.02.3.0 – through 2.3.32.2.0 – through 2.2.42.1.0 – through 2.1.22.0.0 – through 2.0.21.30.0 – through 1.30.81.29.0 – through 1.29.21.28.0 – through 1.28.1 |
Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H