Buffer overflow in MongoDB
CVE-2026-18693
An issue in MongoDB Server's handling of timeseries collections could allow an authenticated user with write privileges to cause an internal data structure to become inconsistent through certain document insertions. A subsequent insert into the affected bucket could then result in the server accessing memory outside its intended bounds, potentially causing a server crash (denial of service), exposure of limited memory contents, or memory corruption.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H.
EPSS exploit prediction
EPSS: 0.003 (24.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 24.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- MongoDB — versions 9.0.0, 9.1.0
- MongoDB Server — versions 8.3.0, 8.0, 7.0
Weakness classification (CWE)
References
- jira.mongodb.org/browse/SERVER-129994 (Issue Tracking, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-18693?
- CVE-2026-18693 is a high-severity vulnerability in MongoDB, classified under Out-of-bounds Write. CVSS score: 7.6/10. Published 2026-08-11.
- How severe is CVE-2026-18693?
- High severity. CVSS v3 base score is 7.6 out of 10.