CVE-2026-106431

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

Published Oct 8, 2026 CVSS 4.0 · 5.9 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

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History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mongodb
Mongodb c Driver
Vendors & Products Mongodb
Mongodb c Driver
Type Values Removed Values Added
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.
Title One-byte heap buffer overflow in BSON bulk document writer in MongoDB C Driver
Weaknesses CWE-787
References
Metrics cvssV3_1

{'score': 5.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H'}

cvssV4_0

{'score': 5.9, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mongodb
Published
Updated
Oct 8, 2026, 7:19 PM
Reserved
Oct 6, 2026, 4:40 PM
Status
Awaiting Analysis
Published
Oct 8, 2026, 7:16 PM
Modified
Oct 8, 2026, 8:49 PM