CVE-2021-23566Public exploit

Prior ID disclosure via repeated size coercion

Published Jan 14, 2022 · Updated Nov 3, 2025

Information exposure in Nano ID 3.0.0 through 3.1.30 allows local users to reproduce the preceding generated ID via a crafted size object. The nanoid and random functions reuse the size object across pool checks and offset arithmetic, so a stateful valueOf method returns different numbers and redirects a read to the prior pool segment. Exploitation requires control of the size argument passed by a local application and reveals only the immediately preceding ID, without reported data modification or service interruption.

CVSS severity5.5
Medium
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information exposure in Nano ID 3.0.0 through 3.1.30 allows local users to reproduce the preceding generated ID via a crafted size object. The nanoid and random functions reuse the size object across pool checks and offset arithmetic, so a stateful valueOf method returns different numbers and redirects a read to the prior pool segment. Exploitation requires control of the size argument passed by a local application and reveals only the immediately preceding ID, without reported data modification or service interruption.

The record

CVE
CVE-2021-23566
Published
Jan 14, 2022
Updated
Nov 3, 2025
Vendor
Nano ID
Product
Nano ID
Classifications
CWE-200, CWE-704
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Jan 14, 2022CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <3.1.31

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Nano ID · Nano IDversion=unspecified <3.1.31

Published CVSS scores

4.0SnykCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
5.5GitHub Security Advisory DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
2.1NVDAV:L/AC:L/Au:N/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
CWE-704Incorrect Type Conversion or Cast

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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