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CVE Record

CVE-2021-23566: Information Exposure

The package nanoid from 3.0.0 and before 3.1.31 are vulnerable to Information Exposure via the valueOf() function which allows to reproduce the last id generated.

MediumCVSS 4Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-23566 affects the JavaScript nanoid package. In vulnerable 3.x releases before 3.1.31, a function can expose enough state to reproduce the last generated ID. Business risk is highest when those IDs are treated as secrets, tokens, or authorization material.

Executive priority

Prioritize remediation as dependency hygiene unless nanoid-generated values secure user access, invitations, resets, or internal object references. In those cases, treat it as a near-term fix because predictable identifiers can weaken confidentiality controls.

Technical view

nanoid 3.0.0 through versions before 3.1.31 are reported vulnerable to information exposure through valueOf(), allowing reproduction of the last generated ID. CVSS 3.1 is 4.0 with local attack vector and low confidentiality impact. Sources identify upstream PR and commit remediation references.

Likely exposure

Exposure is likely in applications or packaged dependencies using nanoid 3.0.0 to 3.1.30, including JavaScript and WebJars packaging. Impact depends on whether generated IDs cross trust boundaries or protect sensitive workflows.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation. It does reference public vulnerability advisories and proof-of-concept material. Treat exploitability as plausible but not proven in the wild from these sources.

Researcher notes

Focus analysis on whether applications expose objects returned by affected nanoid versions or rely on them as unguessable secrets. Evidence supports affected range and upstream fix references, but not active exploitation. Avoid assuming impact where IDs are only non-sensitive labels.

Mitigation direction

  • Upgrade nanoid to 3.1.31 or later where supported.
  • Update transitive dependencies that bundle affected nanoid versions.
  • Check WebJars and Debian package guidance for packaged variants.
  • Review uses where nanoid values act as secrets or access tokens.
  • Rotate exposed identifiers if logs or clients received sensitive generated IDs.

Validation and detection

  • Inspect package manifests and lockfiles for nanoid 3.0.0 through 3.1.30.
  • Check SBOMs for JavaScript, WebJars, and OS-packaged nanoid copies.
  • Confirm deployed builds include the upgraded dependency version.
  • Review application logic for trust decisions based only on generated IDs.
  • Verify security scanners no longer flag CVE-2021-23566.
Prepared
Confidence
high
Sources
7

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-2021-23566 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
4 (3.1)
Known Exploited
No
Published

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

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
8Source 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
4CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:P2.51.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

4Medium
CVSS 3.1 vector shape for CVE-2021-23566Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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/ananoidunspecifiedListed
Weakness

CWE details

No CWE listed

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