Uncontrolled Recursion in MongoDB Server - CVE-2026-9740
Published: August 18, 2026
Vulnerability identifier: #VU144173
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-9740
CWE-ID: CWE-674
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled recursion in BSON validation logic when parsing specially crafted messages containing certain nested binary data structures. A remote attacker can send a specially crafted message to cause a denial of service.
The issue can crash the mongod process because mutual recursion between validation functions resets internal depth tracking.
Affected software
MongoDB Server
How to mitigate CVE-2026-9740
Install security update from vendor's website.
MongoDB Server - addressed in versions 7.0.35, 8.0.24, 8.2.10, 8.3.3