CVE-2026-126838

Rust Driver public Client Debug output exposes CSFLE KMS master-key material

Published Nov 12, 2026 CVSS 4.0 · 5.7 Medium EPSS n/a KEV · Not listed

Description

A MongoDB Rust Driver component that holds client-side field level encryption settings includes key management service credential material in its diagnostic formatting output without redaction. An application that records or displays this formatted output may place that material where a party with read access to the application's diagnostic output can see it, which may result in unintended disclosure of key material.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

MongoDB

Rust Driver

unaffected

Version	Status	Constraints
`3.9.0`	affected	< 3.9.1
`3.8.0`	affected	< 3.8.2
`3.7.0`	affected	—
`3.6.0`	affected	—
`3.5.0`	affected	< 3.5.2
`3.4.0`	affected	< 3.4.1
`3.3.0`	affected	—
`3.2.0`	affected	< 3.2.5
`3.1.0`	affected	< 3.1.1
`3.0.0`	affected	< 3.0.1
`2.8.0`	affected	< 2.8.2
`2.7.0`	affected	< 2.7.1
`2.6.0`	affected	< 2.6.1
`2.5.0`	affected	—
`2.4.0`	affected	—

No data.

Vendor Product Versions

Mongodb

Rust Driver

Version	Status	Scheme	Platform
`[3.9.0,3.9.1)`	affected	semver	—
`[3.8.0,3.8.2)`	affected	semver	—
`3.7.0`	affected	semver	—
`3.6.0`	affected	semver	—
`[3.5.0,3.5.2)`	affected	semver	—
`[3.4.0,3.4.1)`	affected	semver	—
`3.3.0`	affected	semver	—
`[3.2.0,3.2.5)`	affected	semver	—
`[3.1.0,3.1.1)`	affected	semver	—
`[3.0.0,3.0.1)`	affected	semver	—
`[2.8.0,2.8.2)`	affected	semver	—
`[2.7.0,2.7.1)`	affected	semver	—
`[2.6.0,2.6.1)`	affected	semver	—
`2.5.0`	affected	semver	—
`2.4.0`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://jira.mongodb.org/browse/RUST-2531

History

Nov 13, 2026 2:45 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Mongodb Mongodb rust Driver
Vendors & Products		Mongodb Mongodb rust Driver

Nov 12, 2026 7:00 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		A MongoDB Rust Driver component that holds client-side field level encryption settings includes key management service credential material in its diagnostic formatting output without redaction. An application that records or displays this formatted output may place that material where a party with read access to the application's diagnostic output can see it, which may result in unintended disclosure of key material.
Title		Rust Driver public Client Debug output exposes CSFLE KMS master-key material
Weaknesses		CWE-532
References		https://jira.mongodb.org/browse/RUST-2531
Metrics		cvssV3_1 `{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'}` cvssV4_0 `{'score': 5.7, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}`