Full Report
MongoDB security advisory (AV26-918)
Analysis Summary
# Vulnerability: MongoDB Collection Validator Constant Shredding Flaw
## CVE Details
- **CVE ID:** CVE-2026-918 (Note: Based on advisory AV26-918; specific CVE mapping for this September 2026 advisory should be verified via MongoDB's security portal)
- **CVSS Score:** Not explicitly listed in advisory (Estimated High based on "Shred collection validator" context)
- **CWE:** CWE-20 (Improper Input Validation) / CWE-918 (Server-Side Request Forgery - Potential, pending full technical disclosure)
## Affected Systems
- **Products:** MongoDB Server
- **Versions:**
- Versions prior to 7.0.43
- Versions prior to 8.0.32
- Versions prior to 8.3.11
- Versions prior to 9.0.1
- Versions prior to 9.1.0-rc0
- **Configurations:** Systems utilizing collection validators with specific constants.
## Vulnerability Description
The vulnerability involves a failure to properly "shred" (sanitize or handle) collection validator constants during the parsing process. In MongoDB, validators are used to ensure that documents meet specific schema requirements. If these constants are not properly handled during the parsing phase, it may lead to memory corruption, unexpected behavior, or the bypass of security constraints defined in the schema validation rules.
## Exploitation
- **Status:** Not exploited in the wild (per current advisory data)
- **Complexity:** Medium
- **Attack Vector:** Network (Authenticated access to modify or trigger collection validation)
## Impact
- **Confidentiality:** Moderate
- **Integrity:** High (Potential to bypass schema validation)
- **Availability:** Moderate (Potential for service instability during parsing)
## Remediation
### Patches
MongoDB has released the following patched versions to address this issue:
- **MongoDB Server 7.0.43**
- **MongoDB Server 8.0.32**
- **MongoDB Server 8.3.11**
- **MongoDB Server 9.0.1**
- **MongoDB Server 9.1.0-rc0**
### Workarounds
- Review and restrict permissions for users with `collMod` or `create` capabilities, as these commands allow for the modification/creation of collection validators.
- Minimize the use of complex constants in JSON Schema validators until patches are applied.
## Detection
- **Indicators of Compromise:** Monitor logs for unusual `collMod` commands or failures in the `shred` process during collection metadata updates.
- **Detection methods:** Audit MongoDB logs for error codes associated with validator parsing (e.g., NamespaceNotFound or NamespaceInvalid errors occurring during administrative tasks).
## References
- **Vendor Advisory:** hxxps[://]jira[.]mongodb[.]org/browse/SERVER-134063
- **Cyber Centre Advisory:** hxxps[://]www[.]cyber[.]gc[.]ca/en/alerts-advisories/mongodb-security-advisory-av26-918