All vulnerabilities
CVE-2026-106431

One-byte heap buffer overflow in BSON bulk document writer in MongoDB C Driver

MongoDB C DriverDatabases
Open in ThreatlineRecord JSON
CVSS
5.9Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.10%Chance of exploitation activity in the next 30 days, higher than 0% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in1.30.13Also 2.5.6CVE List
Published8 Oct 2026Updated 8 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 2

  • C Driveraffected: 0.5.0 before 1.30.13CVE List
  • C Driveraffected: 2.0.0 before 2.5.6CVE List

References 1