Out-of-bounds read and write via undersized BSON buffer reservation in MongoDB C Driver

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-106437
StatePUBLISHED
Assignermongodb
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-08 19:16:59 UTC
Updated2026-10-08 20:49:23 UTC
DescriptionThe BSON buffer-reservation API in the MongoDB C Driver can record a length smaller than the five-byte BSON minimum. Later append or comparison operations can underflow unsigned length calculations and read or write outside the document buffer. An actor who can influence the length supplied by an embedding application can cause the application to terminate or read or corrupt adjacent process memory. Reaching this issue requires the application to pass an undersized value to bson_reserve_buffer and then perform an affected operation.

Risk And Classification

Primary CVSS: v4.0 5.9 MEDIUM from [email protected]

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-191 | CWE-191 CWE-191: Integer Underflow (Wrap or Wraparound)

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary5.9MEDIUMCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS5.9MEDIUMCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
3.1[email protected]Secondary6.2MEDIUMCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
3.1CNACVSS6.2MEDIUMCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
Low
Integrity
Low
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
High

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA MongoDB C Driver affected 1.4.0 1.30.13 semver Not specified
CNA MongoDB C Driver affected 2.0.0 2.5.6 semver Not specified

References

ReferenceSourceLinkTags
jira.mongodb.org/browse/CDRIVER-6423 [email protected] jira.mongodb.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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