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CVE Record

CVE-2021-23807: Prototype Pollution

This affects the package jsonpointer before 5.0.0. A type confusion vulnerability can lead to a bypass of a previous Prototype Pollution fix when the pointer components are arrays.

MediumCVSS 5.6Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-23807 is a medium-severity flaw in jsonpointer before 5.0.0. Under specific input handling conditions, it can bypass an earlier prototype pollution fix and may let data structures be altered in unintended ways. Business urgency is moderate, focused on dependency exposure rather than confirmed active exploitation.

Executive priority

Prioritize in the normal dependency remediation queue, faster for internet-facing services or systems processing untrusted JSON data. There is no provided evidence of active exploitation, but the issue affects application integrity boundaries and has an available version boundary for remediation.

Technical view

The issue is a type confusion vulnerability in jsonpointer before 5.0.0. When pointer components are arrays, prior prototype pollution protections can be bypassed. The CVSS 3.1 score is 5.6 with network attack vector, high complexity, no privileges, no user interaction, and low confidentiality, integrity, and availability impact.

Likely exposure

Exposure is most likely in applications that directly or transitively depend on jsonpointer versions before 5.0.0. The bundle also references Snyk entries for npm and Java WebJars packaging, so dependency inventory should include both package ecosystems where relevant.

Exploitation context

The provided sources do not show CISA KEV listing or confirmed active exploitation. CVSS marks exploit code maturity as proof-of-concept, but the bundle does not provide operational exploit detail. Treat this as a dependency risk requiring cleanup, not an emergency breach indicator.

Researcher notes

Key evidence is the CVE description, Snyk advisories, and upstream pull request/commit. The important condition is pointer components represented as arrays causing type confusion and bypassing a prior prototype pollution fix. Sources do not provide enough detail to assert affected application behavior without local dependency and data-flow review.

Mitigation direction

  • Upgrade jsonpointer to version 5.0.0 or later where dependency manifests allow.
  • Refresh lockfiles and rebuild artifacts so transitive vulnerable copies are not retained.
  • Check vendor guidance for npm and WebJars packaged variants referenced by Snyk.
  • Reduce trust in externally supplied JSON pointer input until remediation is complete.
  • Document the dependency update and retest affected application workflows.

Validation and detection

  • Inventory manifests and lockfiles for jsonpointer versions below 5.0.0.
  • Include transitive dependencies and WebJars/npm coordinates in SCA scans.
  • Confirm runtime bundles do not include vulnerable jsonpointer copies.
  • Run regression tests around JSON pointer parsing and object mutation behavior.
  • Review SCA output after remediation for CVE-2021-23807 closure.
Prepared
Confidence
high
Sources
6

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-2021-23807 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
Medium
CVSS
5.6 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C

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
5Source 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
5.6CVSS 3.1MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C2.23.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

5.6Medium
CVSS 3.1 vector shape for CVE-2021-23807Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C

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/ajsonpointerunspecifiedListed
Weakness

CWE details

No CWE listed

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