Medium severity · published Oct 8, 2026
CVE-2026-106431
One-byte heap buffer overflow in BSON bulk document writer in MongoDB C Driver
5.7
CVSS
0.1%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Attack vector
Local
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
Low
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 1% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MO
MongoDB · MongoDB
0.5.0 before 1.30.13; 2.0.0 before 2.5.6 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-106431
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-106431
jira.mongodb.org
https://jira.mongodb.org/browse/CDRIVER-6418
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