CVE-2026-8053 Overview
CVE-2026-8053 is an out-of-bounds write vulnerability [CWE-787] in MongoDB Server's time-series collection implementation. An authenticated user with database write privileges can trigger an out-of-bounds memory write in the mongod process. The flaw stems from an inconsistency in the internal field-name-to-index mapping within the time-series bucket catalog. Under specific conditions, exploitation can lead to arbitrary code execution within the MongoDB server process.
The vulnerability affects MongoDB Server versions 5.0, 6.0, 7.0, 8.0, 8.2, and 8.3 prior to their respective fixed releases. MongoDB tracks this issue as SERVER-126021.
Critical Impact
Authenticated attackers with write privileges can achieve arbitrary code execution in the mongod process, compromising database confidentiality, integrity, and availability.
Affected Products
- MongoDB Server v5.0 versions prior to 5.0.33
- MongoDB Server v6.0 versions prior to 6.0.28, v7.0 versions prior to 7.0.34
- MongoDB Server v8.0 versions prior to 8.0.23, v8.2 versions prior to 8.2.9, v8.3 versions prior to 8.3.2
Discovery Timeline
- 2026-05-13 - CVE-2026-8053 published to NVD
- 2026-05-13 - Last updated in NVD database
Technical Details for CVE-2026-8053
Vulnerability Analysis
The vulnerability resides in MongoDB's time-series collection subsystem, which stores data as compressed buckets indexed by measurement field names. The bucket catalog maintains an internal mapping between field names and their corresponding column indices. When this mapping becomes inconsistent during specific write operations, the server writes data beyond the bounds of an allocated memory region.
Out-of-bounds writes [CWE-787] in a database server process create conditions favorable for memory corruption exploitation. Adjacent heap structures, function pointers, or control data may be overwritten, enabling arbitrary code execution within the mongod process context. Because mongod typically holds privileged access to all data stores it manages, successful exploitation compromises every collection on the affected instance.
Root Cause
The root cause is an inconsistency in the field-name-to-index mapping inside the time-series bucket catalog. When the catalog state diverges from the actual bucket layout, write operations reference indices that fall outside the intended buffer boundary. The flaw is reachable through normal write operations against time-series collections, requiring no special administrative privileges beyond standard database write access.
Attack Vector
Exploitation requires network access to the MongoDB instance and authenticated credentials with write privileges on a target database. An attacker issues crafted insert or update operations against a time-series collection to induce the inconsistent catalog state. The vulnerability is network-reachable, has low attack complexity, and requires no user interaction. Refer to the MongoDB Jira Ticket SERVER-126021 for vendor tracking details.
Detection Methods for CVE-2026-8053
Indicators of Compromise
- Unexpected mongod process crashes or segmentation faults logged in MongoDB server logs, particularly during time-series write operations.
- Anomalous child processes spawned by mongod, indicating possible post-exploitation command execution.
- Outbound network connections from MongoDB hosts to unfamiliar destinations following authenticated client write activity.
Detection Strategies
- Audit MongoDB server logs for assertion failures, invariant violations, or stack traces referencing time-series bucket catalog code paths.
- Enable MongoDB auditing to record write operations against time-series collections and correlate with user accounts holding write privileges.
- Monitor mongod process memory regions and crash dumps for signatures consistent with heap corruption.
Monitoring Recommendations
- Track MongoDB Server version inventory and flag instances running versions earlier than 5.0.33, 6.0.28, 7.0.34, 8.0.23, 8.2.9, or 8.3.2.
- Alert on privilege grants that add write roles to non-administrative accounts on databases containing time-series collections.
- Baseline normal mongod resource usage and detect deviations indicative of exploitation attempts.
How to Mitigate CVE-2026-8053
Immediate Actions Required
- Upgrade MongoDB Server to a patched release: 5.0.33, 6.0.28, 7.0.34, 8.0.23, 8.2.9, or 8.3.2.
- Review and minimize accounts holding readWrite or equivalent write privileges on databases that contain time-series collections.
- Rotate credentials for any service accounts with write access to MongoDB instances exposed beyond trusted network segments.
Patch Information
MongoDB has released fixed versions for all supported branches. Apply the upgrade for your deployment series: v5.0 → 5.0.33, v6.0 → 6.0.28, v7.0 → 7.0.34, v8.0 → 8.0.23, v8.2 → 8.2.9, v8.3 → 8.3.2. See the MongoDB Jira Ticket SERVER-126021 for the official tracking entry.
Workarounds
- Restrict network access to mongod listeners using firewall rules so only trusted application hosts can reach the database port.
- Remove or disable time-series collections in environments where they are not required until patching completes.
- Enforce least-privilege role assignments and audit existing user roles to remove unnecessary write permissions.
# Verify MongoDB Server version and review users with write privileges
mongosh --eval 'db.version()'
mongosh --eval 'db.getSiblingDB("admin").system.users.find({}, {user:1, roles:1}).pretty()'
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
