Use After Free in MongoDB
CVE-2026-18706
An issue in MongoDB Server's $graphLookup aggregation stage could allow an authenticated user able to issue aggregation and memory-management commands to cause an internal reference to be used after the underlying memory has been freed. This could result in a server crash or, potentially, execution of unintended code.
Vulnerability class: Use-After-Free
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.6 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.005 (37.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 38th percentile — 37.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.001
Affected products
- MongoDB — versions 9.0.0
- MongoDB Server — versions 8.3.0
Weakness classification (CWE)
References
- jira.mongodb.org/browse/SERVER-128551 (Issue Tracking, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-18706?
- CVE-2026-18706 is a medium-severity vulnerability in MongoDB, classified under Use After Free. CVSS score: 6.6/10. Published 2026-08-11.
- How severe is CVE-2026-18706?
- Medium severity. CVSS v3 base score is 6.6 out of 10.