Full Report
MongoDB security advisory (AV26-468)
Analysis Summary
# Vulnerability: MongoDB Time-Series Collection Undefined Behavior
## CVE Details
- **CVE ID:** CVE-2026-8053
- **CVSS Score:** Not explicitly provided in the advisory (Typically rated Medium to High for data integrity issues)
- **CWE:** CWE-444 / CWE-119 (Implied: Undefined behavior/Consistency issues)
## Affected Systems
- **Products:** MongoDB Server
- **Versions:**
- 8.3.0 to 8.3.1
- 8.2.0 to 8.2.8
- 8.0.0 to 8.0.22
- 7.0.0 to 7.0.33
- 6.0.0 to 6.0.27
- 5.0.0 to 5.0.32
- **Configurations:** Systems utilizing **Time-Series collections**.
## Vulnerability Description
The vulnerability stems from **undefined behavior** triggered during data insertion into time-series collections. Specifically, when a user attempts to insert data containing **duplicate field names**, the database engine handles the conflict improperly. In a time-series context—where data is often compressed and bucketed internally—this can lead to unexpected internal states or data inconsistencies.
## Exploitation
- **Status:** Not reported as exploited in the wild (per initial advisory).
- **Complexity:** Low (Requires only the ability to perform inserts).
- **Attack Vector:** Network (Authenticated database user with 'insert' permissions).
## Impact
- **Confidentiality:** Low/None
- **Integrity:** **High** (Risk of data corruption or inconsistent query results).
- **Availability:** **Medium** (Potential for service instability or crashes due to undefined behavior).
## Remediation
### Patches
MongoDB has released the following patched versions. Users are encouraged to upgrade immediately to the relevant branch:
- MongoDB 8.3.2 or later
- MongoDB 8.2.9 or later
- MongoDB 8.0.23 or later
- MongoDB 7.0.34 or later
- MongoDB 6.0.28 or later
- MongoDB 5.0.33 or later
### Workarounds
- **Input Validation:** Implement application-side schema validation to ensure documents do not contain duplicate keys before reaching the database.
- **Access Control:** Restrict `insert` permissions on time-series collections to trusted applications/users only.
## Detection
- **Indicators of Compromise:** Unusual log entries related to "Storage Engines" or "BSON validation" warnings.
- **Detection Methods:** Audit existing time-series collections for duplicate fields using the `aggregation` framework or administrative scripts to identify inconsistent data structures.
## References
- **Vendor Advisory:** hxxps[://]jira[.]mongodb[.]org/browse/SERVER-126021
- **Cyber Centre Bulletin:** hxxps[://]www[.]cyber[.]gc[.]ca/en/alerts-advisories/mongodb-security-advisory-av26-468