Vulnerability · Published Sep 24, 2026 · Assigned by mongodb
CVE-2026-96746Heap buffer overflow via mid-scan command list growth in client topology monitoring
Medium 6.5
In plain English
A medium-severity out-of-bounds write in C Driver from MongoDB. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | mongo-c-driver | no fix listed | DEBIAN-CVE-2026-96746 |
| Debian:13 | mongo-c-driver | no fix listed | DEBIAN-CVE-2026-96746 |
| Debian:14 | mongo-c-driver | 2.5.5-1 | DEBIAN-CVE-2026-96746 |
| Ubuntu:22.04:LTS | pymongo | no fix listed | UBUNTU-CVE-2026-96746 |
| Ubuntu:24.04:LTS | pymongo | no fix listed | UBUNTU-CVE-2026-96746 |
| Ubuntu:26.04:LTS | pymongo | no fix listed | UBUNTU-CVE-2026-96746 |
| Ubuntu:26.10 | pymongo | no fix listed | UBUNTU-CVE-2026-96746 |
Affected products (as reported)
Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H