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CVE Record

CVE-2021-23440: Prototype Pollution

This affects the package set-value before <2.0.1, >=3.0.0 <4.0.1. A type confusion vulnerability can lead to a bypass of CVE-2019-10747 when the user-provided keys used in the path parameter are arrays.

HighCVSS 7.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-23440 affects the JavaScript set-value package. If an application accepts untrusted input for object paths, specially shaped keys can pollute shared object prototypes, potentially causing unintended behavior across the application. The issue is high severity, but the provided sources do not show confirmed active exploitation.

Executive priority

Prioritize remediation for internet-facing or multi-tenant applications that process user-controlled structured data. Treat this as a dependency hygiene and application integrity risk rather than a confirmed active incident based on the provided evidence.

Technical view

The flaw is prototype pollution in set-value caused by type confusion in the path parameter. User-provided path keys supplied as arrays can bypass the earlier CVE-2019-10747 protection. Affected ranges are set-value versions before 2.0.1 and versions 3.0.0 through before 4.0.1.

Likely exposure

Exposure is most likely in Node.js or bundled JavaScript applications that directly or transitively include vulnerable set-value versions and pass untrusted path data into the library. WebJars packaging may also matter where org.webjars.npm artifacts are used.

Exploitation context

The CVSS vector indicates network-reachable, unauthenticated, low-complexity exploitation with limited confidentiality, integrity, and availability impact. The bundle marks CISA KEV as false, and no provided source confirms exploitation in the wild.

Researcher notes

Focus analysis on reachability: vulnerable versions alone are not enough if untrusted data cannot influence the path parameter. The notable technical detail is array-based path input bypassing the prior CVE-2019-10747 fix. Avoid assuming impact beyond prototype pollution without application-specific sinks.

Mitigation direction

  • Upgrade set-value to a non-affected version, such as 2.0.1 or 4.0.1 or later.
  • Update transitive dependencies and regenerate lockfiles through normal package management.
  • Review Snyk and upstream GitHub advisories for version-specific guidance.
  • If using WebJars or Oracle software, review the linked vendor advisories.
  • Avoid passing untrusted path arrays into object mutation helpers.

Validation and detection

  • Search SBOMs, package manifests, and lockfiles for set-value versions in affected ranges.
  • Confirm runtime bundles do not include vulnerable transitive copies.
  • Check whether application inputs can control the set-value path parameter.
  • Verify dependency scanners report CVE-2021-23440 as remediated after upgrades.
  • Document any accepted exposure where upgrade is blocked.
Prepared
Confidence
high
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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-2021-23440 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.3 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Official CVE source material

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.

1CVSS vectors
0Timeline events
0ADP providers
7Source links

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
7.3CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L3.93.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.3High
CVSS 3.1 vector shape for CVE-2021-23440Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/aset-value<2.0.1, >=3.0.0 <4.0.1Listed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.