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Full vulnerability report · 2021
CVE-2021-20333High confidence

Server log entry spoofing via newline injection

MongoDB Inc. · MongoDB Server

5.3MediumCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:High, raised one band.upgradedsince 17 Sep 2024

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • A structured source references public exploit or proof-of-concept material.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 1.28% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs MongoDB Inc. MongoDB Server and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
9AKK108472A9037 · CSAF 2.0 · revision 1 · finalABB Product Security Incident Response Team (PSIRT)CVE-2021-20333
1 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • IIoT services with MongoDB 4.2 installed on ABB Ability Zenon /all
Summary
Sending specially crafted commands to a MongoDB Server may result in artificial log entries being generated or for log entries to be split. This issue affects MongoDB Server v3.6 versions prior to 3.6.20; MongoDB Server v4.0 versions prior to 4.0.21 and MongoDB Server v4.2 versions prior to 4.2.10.
Remediation
ABB recommends the following mitigation measures: - Replace bundled MongoDB with a supported version if IIoT services are required: - Where IIoT functionality is required, the bundled MongoDB instance can be replaced with a supported and patched version through manual configuration. - The following zenon online help section explains the process of installing and using your own MongoDB database: zenHelpViewer - Uninstall IIoT Services wherever it’s not required: - If IIoT Services are not required, they can be removed using the Control panel uninstaller. This eliminates the dependency on MongoDB without affecting other zenon components. Refer to section “General security recommendations” for further advise on how to keep your system secure.
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2021-7751

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

Sending specially crafted commands to a MongoDB Server may result in artificial log entries being generated or for log entries to be split. This issue affects MongoDB Server v3.6 versions prior to 3.6.20; MongoDB Server v4.0 versions prior to 4.0.21 and MongoDB Server v4.2 versions prior to 4.2.10.

What

Sending specially crafted commands to a MongoDB Server may result in artificial log entries being generated or for log entries to be split. This issue affects MongoDB Server v3.6 versions prior to 3.6.20; MongoDB Server v4.0 versions prior to 4.0.21 and MongoDB Server v4.2 versions prior to 4.2.10.

Why

The product constructs a log message from external input, but it does not neutralize or incorrectly neutralizes special elements when the message is written to a log file.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Sending specially crafted commands to a MongoDB Server may result in artificial log entries being generated or for log entries to be split. This issue affects MongoDB Server v3.6 versions prior to 3.6.20; MongoDB Server v4.0 versions prior to 4.0.21 and MongoDB Server v4.2 versions prior to 4.2.10.

Why

The product constructs a log message from external input, but it does not neutralize or incorrectly neutralizes special elements when the message is written to a log file.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Improper Output Neutralization for Logs → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-117 ↗

CWE-117: Improper Output Neutralization for Logs. The product constructs a log message from external input, but it does not neutralize or incorrectly neutralizes special elements when the message is written to a log file.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-117Public exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

Cyber Security Agency of Singapore · English · CSA-SB-20210728Security Bulletin 28 Jul 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 28 Jul 2021, published on 28 July 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-574Vulnérabilité dans MongoDB

Une vulnérabilité a été découverte dans MongoDB. Elle permet à un attaquant de provoquer une atteinte à l'intégrité des données.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-010188MongoDB Server におけるエンコードおよびエスケープに関する脆弱性

MongoDB Server には、エンコードおよびエスケープに関する脆弱性が存在します。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix availability varies by product
Affected
IIoT services with MongoDB 4.2 installed on ABB Ability Zenon /all
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
ABB recommends the following mitigation measures: - Replace bundled MongoDB with a supported version if IIoT services are required: - Where IIoT functionality is required, the bundled MongoDB instance can be replaced with a supported and patched version through manual configuration. - The following zenon online help section explains the process of installing and using your own MongoDB database: zenHelpViewer - Uninstall IIoT Services wherever it’s not required: - If IIoT Services are not required, they can be removed using the Control panel uninstaller. This eliminates the dependency on MongoDB without affecting other zenon components. Refer to section “General security recommendations” for further advise on how to keep your system secure.
04

Evidence and provenance

Published 23 Jul 2021 · Last source change 17 Sept 2024, 03:08 UTC · CWE-117 · Improper Output Neutralization for Logs

CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2021-7751
Product sourceVendor CSAF · ABB Product Security Incident Response Team (PSIRT)
Remediation sourceVendor CSAF · ABB Product Security Incident Response Team (PSIRT)
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed: added remediation: search.abb.com/Download.aspx?DocumentID=9AKK108472A9037&LanguageCode=en&DocumentPartId=pdf&Action=Launch; removed remediation: nvd.nist.gov/CVE-2021-20333.
    Before
    remediation: nvd.nist.gov/CVE-2021-20333
    After
    remediation: search.abb.com/Download.aspx?DocumentID=9AKK108472A9037&LanguageCode=en&DocumentPartId=pdf&Action=Launch
    ABB Product Security Incident Response Team (PSIRT) ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2021-7751↗Vendor CSAF · ABB Product Security Incident Response Team (PSIRT)↗Public exploit reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2021-20333 · cve.blacktree.nl