Security readout for executives and security teams
Plain-English summary
This is an availability issue in older MongoDB Server releases. A logged-in user who can run queries may be able to crash the mongod process using specially crafted queries involving compound indexes. It does not indicate data theft or privilege escalation, but it can interrupt applications that depend on vulnerable MongoDB instances.
Executive priority
Treat this as a moderate availability risk. Prioritize remediation for business-critical or externally reachable MongoDB systems, especially where many users or applications have query access. It is less urgent than unauthenticated remote code execution, but unplanned database outages can still affect revenue and operations.
Technical view
CVE-2018-20802 affects MongoDB Server 3.6 before 3.6.9 and 4.0 before 4.0.3. The flaw is in QueryPlanner handling of post-auth database queries with compound indexes, allowing a low-privileged authenticated user to trigger denial of service. CVSS 3.1 is 6.5 with high availability impact only.
Likely exposure
Exposure is limited to MongoDB Server 3.6.x below 3.6.9 or 4.0.x below 4.0.3 where users can authenticate and run database queries. Internet exposure increases operational risk, but the source bundle does not identify unauthenticated impact.
Exploitation context
The source bundle does not show active exploitation, and KEV is false. Exploitation requires a user already authorized to perform database queries. The practical impact is service interruption from a mongod crash, not confidentiality or integrity compromise.
Researcher notes
Evidence is concise: the CVE record identifies a post-auth denial-of-service condition in QueryPlanner involving compound indexes, with affected version bounds. No public exploit status or detailed root-cause analysis is included in the supplied bundle beyond the MongoDB Jira reference.
Mitigation direction
- Upgrade MongoDB Server 3.6 deployments to 3.6.9 or later.
- Upgrade MongoDB Server 4.0 deployments to 4.0.3 or later.
- Confirm current vendor guidance before changing unsupported legacy deployments.
- Limit database query privileges to users with a clear business need.
- Restrict network access to MongoDB from trusted application and administration paths.
Validation and detection
- Inventory MongoDB Server versions across production, staging, and backups.
- Flag 3.6.x versions below 3.6.9 and 4.0.x versions below 4.0.3.
- Review authenticated database users with query permissions.
- Check monitoring for unexplained mongod crashes or restarts.
- Avoid crafted-query validation in production environments.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-394: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupDatabase behavior lookup
The CVE wording references database injection or access, so collection and exfiltration review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2018-20802 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H2.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://jira.mongodb.org/browse/SERVER-36993CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Unexpected Status Code or Return Value
Unexpected Status Code or Return Value represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.