CVE-2026-93395

MEDIUM CVSS 4.0: 6.9 EPSS 0.40%
Updated Sep 25, 2026
MongoDB
Parameter Value
CVSS 6.9 (MEDIUM)
Affected Versions 2.0.0 — 2.3.1
Fixed In 2.3.1
Type CWE-191 (Integer Underflow)
Vendor MongoDB
Public PoC No

A missing lower-bound validation in the bson_new_from_buffer() function of libbson allows an integer underflow when processing BSON data with a zero-length prefix. The function reads a 32-bit document length from the input buffer but does not verify that the value is at least 5 (the minimum valid BSON document size) before using it in an array index calculation. When the length field is zero, the expression used to check the document's null terminator wraps to UINT32_MAX, causing a heap out-of-bounds read that crashes the process.

An unauthorized party who can supply crafted BSON input to an application using this API can cause a denial of service.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
Low
Partial disruption

CVSS Vector v4.0

Weakness Type (CWE)

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Mongodb C_Driver
cpe:2.3:a:mongodb:c_driver:*:*:*:*:*:mongodb:*:*
2.0.0 2.3.1