CVE-2026-106431
Medium
Description
An off-by-one error in the BSON bulk document writer in the MongoDB C Driver can write one zero byte immediately past a heap allocation when a document ends at a specific buffer boundary. An actor who can influence the size of documents serialized by an embedding application can corrupt adjacent process memory or terminate the process. Reaching this issue requires the application to use the BSON bulk-writer API and produce a precise cumulative document size.
SeverityMedium
CVSS5.7
Exploit probability—
Product
C Driver
PublishedOct 8, 2026
First seenOct 8, 2026
Weakness typeCWE-787Out-of-bounds write
How to fix
Update
- MongoDB C Driver1.30.13, 2.5.6 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| MongoDB C Driver | 0.5.0 ≤ v < 1.30.13, 2.0.0 ≤ v < 2.5.6 | 1.30.13, 2.5.6 |
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