Auth bypass in MongoDB
CVE-2026-18709
An issue in MongoDB Server could allow an authenticated user with direct network access to a shard to improperly commit or abort an in-progress prepared transaction, bypassing the intended transaction coordination process. This could result in cross-shard data inconsistency, cluster clock corruption, and violation of transaction atomicity guarantees.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (8.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 8.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · 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-130544 (Issue Tracking, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-18709?
- CVE-2026-18709 is a medium-severity vulnerability in MongoDB, classified under Missing Authorization. CVSS score: 6.4/10. Published 2026-08-11.
- How severe is CVE-2026-18709?
- Medium severity. CVSS v3 base score is 6.4 out of 10.