Answer in brief
CVE-2026-126838 records a Medium severity (CVSS 5.7) vulnerability in Rust Driver public Client Debug output exposes CSFLE KMS master-key material. The current sources do not mark it as known exploited. The current feed maps MongoDB/Rust Driver (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps MongoDB/Rust Driver (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| MongoDB/Rust Drivergeneric | >=3.9.0 <3.9.1 || >=3.8.0 <3.8.2 || 3.7.0 || 3.6.0 || >=3.5.0 <3.5.2 || >=3.4.0 <3.4.1 || 3.3.0 || >=3.2.0 <3.2.5 || >=3.1.0 <3.1.1 || >=3.0.0 <3.0.1 || >=2.8.0 <2.8.2 || >=2.7.0 <2.7.1 || >=2.6.0 <2.6.1 || 2.5.0 || 2.4.0 | 3.9.1, 3.8.2, 3.5.2, 3.4.1, 3.2.5, 3.1.1, 3.0.1, 2.8.2, 2.7.1, 2.6.1 |
Published upstream
Nov 12, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 12, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 12, 2026
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.
Quoted source text, attributed separately from HOL analysis.