Security readout for executives and security teams
Plain-English summary
CVE-2018-16489 affects the JavaScript package just-extend before version 4.0.0. It can let an attacker add unexpected properties to shared JavaScript object prototypes, which may cause unsafe behavior in applications that use the package. Public sources do not provide a CVSS score or confirm active exploitation.
Executive priority
Treat as a dependency hygiene issue with moderate priority unless the package is used in security-sensitive request handling. Prioritize internet-facing applications and services processing untrusted input.
Technical view
The issue is prototype pollution in just-extend <4.0.0 through its functions, allowing properties to be injected onto Object.prototype. The CVE record lists CWE-400 and no CVSS details. Impact depends heavily on how the vulnerable library is used by the application and whether polluted properties influence security-sensitive logic.
Likely exposure
Exposure is most likely in Node.js or JavaScript applications that directly or transitively depend on just-extend versions below 4.0.0. Organizations should check dependency manifests, lockfiles, and SBOMs for the package and version range.
Exploitation context
The source bundle does not show CISA KEV listing, active exploitation, public exploit maturity, or a complete impact chain. Prototype pollution can become serious when application code trusts inherited properties, but exploitability is application-specific.
Researcher notes
The public CVE text is sparse. The key fact is Object.prototype pollution in just-extend <4.0.0. No CVSS vector, patch advisory text, or exploitation evidence is included in the provided sources. Validate impact in the consuming application context.
Mitigation direction
- Upgrade just-extend to a version outside the affected <4.0.0 range.
- Check vendor or package maintainer guidance for fixed-version details.
- Rebuild and redeploy applications after dependency updates.
- Review transitive dependencies that may pull in vulnerable just-extend versions.
Validation and detection
- Search SBOMs, package manifests, and lockfiles for just-extend.
- Confirm no deployed application uses just-extend below 4.0.0.
- Run dependency scanning against production and build environments.
- Review application code for reliance on inherited object properties.
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-400: 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-2018-16489 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://hackerone.com/reports/430291CVE 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.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.