CVE-2026-18709

Missing Authorization in MongoDB Sharded Transaction Commit/Abort Handling Leads to Cross-Shard Data Inconsistency

CVE-2026-18709 is fixed in MongoDB on 1 platform by MongoDB 8.3.11 (version 8.3.11), released September 9, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine

CVSS

5.9

No vendor severity

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0020

9th percentile

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.

Where it's fixed

Product	Fixed in	Fix	Released
Windows apps
MongoDB	8.3.11	MongoDB 8.3.11	Sep 9, 2026

Details

Published
August 11, 2026
Weakness
CWE-862: Missing Authorization
Vendor advisory
https://nvd.nist.gov/vuln/detail/CVE-2026-18709

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