Security readout for executives and security teams
Plain-English summary
CVE-2018-3722 affects the npm merge-deep module before 3.0.1. A malicious input object can change Object.prototype, making attacker-controlled properties appear on all objects in the application process. Business impact depends on where the library handles untrusted data.
Executive priority
Prioritize remediation where merge-deep processes external input in internet-facing services. Without evidence of active exploitation or CVSS scoring, this is not automatically emergency-level, but prototype pollution can create serious application-specific risk.
Technical view
This is a CWE-471 Modification of Assumed-Immutable Data issue, commonly seen as prototype pollution. merge-deep before 3.0.1 allowed __proto__ handling during deep merge, enabling modification of the base Object prototype and affecting later object property lookups.
Likely exposure
Exposure is limited to applications or dependencies using merge-deep versions before 3.0.1, especially where user-controlled objects are merged. The source bundle does not identify specific downstream products or deployments.
Exploitation context
The CVE describes malicious users modifying Object.prototype through __proto__. The bundle includes a HackerOne report and fixing commit, but KEV is false and no cited source states active exploitation in the wild.
Researcher notes
The available evidence supports affected package, vulnerable version range, weakness class, and fixed version boundary. It does not establish exploit prevalence, downstream product impact, or universal business impact. Validate reachability in each application context.
Mitigation direction
- Upgrade merge-deep to version 3.0.1 or later.
- Check vendor guidance and the linked fixing commit before applying compensating controls.
- Avoid passing untrusted objects into vulnerable merge paths before upgrade.
- Review dependency trees for transitive merge-deep usage.
Validation and detection
- Search package lockfiles and SBOMs for merge-deep versions before 3.0.1.
- Identify code paths that merge user-controlled JSON or request data.
- Confirm production builds no longer resolve vulnerable merge-deep versions.
- Retest application behavior after upgrade for merge-related regressions.
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
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CWE-471: Exact CWE lookup
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Open ATT&CK lookupCVE-2018-3722 mapping review
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Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/jonschlinkert/merge-deep/commit/2c33634da7129a5aefcc262d2fec2e72224404e5CVE reference · x_refsource_MISC
- https://hackerone.com/reports/310708CVE 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.
Modification of Assumed-Immutable Data (MAID)
Modification of Assumed-Immutable Data (MAID) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.