Cross-database write retargeting via unvalidated dotted database name in Client.BulkWrite in the MongoDB Go Driver (CVE-2026-81521) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-81521

Cross-database write retargeting via unvalidated dotted database name in Client.BulkWrite in the MongoDB Go Driver

Answer in brief

CVE-2026-81521 records a Unknown severity vulnerability in Cross-database write retargeting via unvalidated dotted database name in Client.BulkWrite in the MongoDB Go Driver. The current sources do not mark it as known exploited. The current feed maps MongoDB/GO 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.

Published Aug 27, 2026Updated Aug 27, 2026Source checked Aug 27, 2026First seen by HOL Aug 27, 2026Material review Aug 27, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. 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.

Affected scope and exposure questions

The current feed maps MongoDB/GO Driver (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
MongoDB/GO Drivergeneric	>=2.1.0 <2.8.2	2.8.2

Recommended response

Check inventory. Check lockfiles and deployed manifests for MongoDB/GO Driver.
Review the reported fix. Update MongoDB/GO Driver to 2.8.2 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 27, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 27, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 27, 2026

Sources and claim methodology

Source referencepkg.go.dev

Upstream source description

The MongoDB Go Driver's client-level bulk write operation may accept a caller-supplied database name containing a reserved separator character without escaping it before the name is used to build the target namespace for the operation. An application that passes untrusted input as a database name could therefore have the write directed at a database and collection other than the ones it intended. Only the Client.BulkWrite API is affected.

Quoted source text, attributed separately from HOL analysis.