Security readout for executives and security teams
Plain-English summary
MongoDB Server 4.4 before 4.4.4 can be crashed or made unavailable by an authenticated user running a particular find query. The main business impact is service interruption, not data theft or modification. Exposure is most relevant where untrusted or broadly privileged users can query MongoDB directly.
Executive priority
Prioritize remediation for internet-reachable, customer-facing, or multi-tenant MongoDB 4.4 deployments. For tightly restricted internal databases, handle through normal patch management, but do not ignore it because the impact is full service availability loss.
Technical view
CVE-2021-20326 is an input-validation flaw in MongoDB Server 4.4 prior to 4.4.4. A low-privileged authenticated user authorized to perform a specific find query can trigger denial of service in mongod. CVSS 3.1 is 6.5 with high availability impact and no confidentiality or integrity impact.
Likely exposure
Organizations running MongoDB Server 4.4 versions earlier than 4.4.4 are potentially exposed. Risk depends on whether users or applications with low-level query privileges can reach mongod. Systems already upgraded beyond 4.4.4, or not running 4.4, are not identified as affected in the supplied sources.
Exploitation context
The provided sources do not report active exploitation, and the CVE is not marked in CISA KEV. Exploitation requires network access plus valid privileges to run the relevant find query. Treat direct database access by tenants, customers, or many internal users as the main risk amplifier.
Researcher notes
The source detail is limited: it identifies a specific find-query denial of service, affected version range, CWE-20, and CVSS vector. It does not provide root cause depth, exploit maturity, or alternate mitigations beyond moving past the affected version range. Avoid assuming other MongoDB branches are affected without vendor evidence.
Mitigation direction
- Upgrade affected MongoDB Server 4.4 deployments to 4.4.4 or later.
- Check MongoDB vendor guidance and release notes before production rollout.
- Limit direct mongod access to trusted applications and administrators.
- Review database user privileges and remove unnecessary find query access.
- Ensure monitoring detects mongod crashes or unexpected availability drops.
Validation and detection
- Inventory MongoDB Server versions across production and non-production environments.
- Confirm no MongoDB Server 4.4 deployment remains below 4.4.4.
- Review accounts and applications with direct query privileges.
- Check logs and monitoring for unexplained mongod restarts or crashes.
- Validate application compatibility after upgrading in a test environment.
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-20: 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 lookupCVE-2021-20326 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-53929CVE reference · x_refsource_MISC
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.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.