Security readout for executives and security teams
Plain-English summary
CVE-2021-23700 affects the JavaScript package merge-deep2. If an application merges attacker-controlled objects with mergeDeep(), an attacker may corrupt shared object behavior. Business impact depends on where the package is used, but sources rate it medium with possible integrity and availability effects.
Executive priority
Treat this as a moderate dependency risk. Prioritize internet-facing services and APIs that process user-supplied JSON or configuration data, but avoid emergency handling unless local validation shows reachable use with untrusted input.
Technical view
All versions of merge-deep2 are reported vulnerable to prototype pollution through mergeDeep(). The CVSS 3.1 vector is network-accessible, low complexity, no privileges, and no user interaction, with low integrity and availability impact. The provided sources do not list a CWE or a confirmed fixed version.
Likely exposure
Exposure is most likely in Node.js or JavaScript applications that depend on merge-deep2 directly or transitively and pass untrusted object data into mergeDeep(). Systems that only bundle the package without reachable untrusted merge paths have lower practical exposure.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation evidence. CVSS marks exploit code maturity as proof-of-concept. Public advisory coverage exists through Snyk, but the provided evidence does not establish real-world exploitation.
Researcher notes
Prototype pollution impact is application-specific. The main research task is reachability: identify mergeDeep() call sites, trace input control, and determine whether polluted properties influence authorization, configuration, serialization, or availability-sensitive code. The provided sources do not name a fix.
Mitigation direction
- Inventory direct and transitive use of merge-deep2.
- Check vendor and advisory guidance for patched or replacement versions.
- Avoid passing untrusted objects into mergeDeep().
- Replace merge-deep2 if no fixed version is available.
- Add input validation for object keys before deep merge operations.
Validation and detection
- Search dependency manifests and lockfiles for merge-deep2.
- Confirm whether mergeDeep() is reachable from external input.
- Review request, API, and configuration merge paths.
- Check SCA results against CVE-2021-23700 or SNYK-JS-MERGEDEEP2-1727593.
- Verify mitigation with focused unit tests for unsafe object keys.
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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CVE-2021-23700 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L/E:P
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:N/UI:N/S:U/C:N/I:L/A:L/E:P3.92.5Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L/E:P
Source materials
- CVE List V5 sourceCVE List V5
- https://snyk.io/vuln/SNYK-JS-MERGEDEEP2-1727593CVE 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.