Answer in brief
CVE-2026-81527 records a Medium severity (CVSS 6.5) vulnerability in NoSQL injection via unquoted constant GroupBy keys in LINQ pipeline translation. The current sources do not mark it as known exploited. The current feed maps MongoDB/C# 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 6.5. 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/C# Driver (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:mongodb:c\#_driver:*:*:*:*:*:mongodb:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| MongoDB/C# Drivergeneric | >=2.14.0 <3.11.1 | 3.11.1 |
Published upstream
Aug 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 29, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 27, 2026
A NoSQL/expression injection weakness exists in the LINQ-to-aggregation query translation layer of the MongoDB C# Driver, in both aggregation expression and query filter translation. When application-supplied values are embedded in certain query constructs, special elements contained within those values are not properly escaped before the resulting query is transmitted to the database, so portions of the value may be interpreted by the database as query logic rather than as data. A user able to supply values that an application incorporates into an affected query may thereby cause unintended data to be returned or query results to be altered.
Quoted source text, attributed separately from HOL analysis.