What’s Vulnerable › Vulnerabilities
CVE-2026-106431: One-byte heap buffer overflow in BSON bulk document writer in MongoDB C Driver
- Severity: medium (CVSS 5.7 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.1% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-10-08 · updated 2026-10-08
- Weakness: CWE-787
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.
Affected products
- MongoDB C# Driver: from 0.5.0 before 1.30.13; from 2.0.0 before 2.5.6 — fixed in 1.30.13, 2.5.6
How to fix
Upgrade to a fixed version: MongoDB C# Driver 1.30.13, 2.5.6. Check the vendor advisory for mitigations.
References
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