---
id: CVE-2026-73086
title: 'nanoid is a secure, URL-friendly, unique string ID generator for JavaScript'
summary: >-
  nanoid is a secure, URL-friendly, unique string ID generator for JavaScript.
  Prior to versions 3.3.12 and 5.1.11, the nanoid(size) function in index.js and
  index.cjs coerces the user-influenced size parameter to a signed 32-bit
  integer, …
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-190
vendor: nanoid
product: nanoid
affected:
  - nanoid < 3.3.12
  - 'nanoid >= 4.0.0, < 5.1.11'
patched:
  - nanoid 3.3.12
  - nanoid 5.1.11
published: '2026-08-11'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T20:46:02.457'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73086'
references:
  - url: >-
      https://github.com/ai/nanoid/commit/7087969281cab8ba8ae3babf1894e819068b3bb4
    label: security-advisories@github.com
  - url: >-
      https://github.com/ai/nanoid/commit/821dfed7b5db7f88e92f56c60eef32c8135077c3
    label: security-advisories@github.com
  - url: >-
      https://github.com/ai/nanoid/commit/b0036ed60dc9facd7f1191a50dfb3076500202ac
    label: security-advisories@github.com
  - url: 'https://github.com/ai/nanoid/releases/tag/3.3.12'
    label: security-advisories@github.com
  - url: 'https://github.com/ai/nanoid/releases/tag/5.1.11'
    label: security-advisories@github.com
  - url: 'https://github.com/ai/nanoid/security/advisories/GHSA-xwg4-73v4-xw9w'
    label: security-advisories@github.com
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73086'
  - url: 'https://github.com/advisories/GHSA-xwg4-73v4-xw9w'
tags:
  - nvd
  - ghsa
  - npm
epss: 0.00296
epssPercentile: 0.22544
aliases:
  - GHSA-xwg4-73v4-xw9w
ecosystem: npm
ingestedAt: '2026-09-01T19:31:23.069Z'
---

## Overview

nanoid is a secure, URL-friendly, unique string ID generator for JavaScript. Prior to versions 3.3.12 and 5.1.11, the nanoid(size) function in index.js and index.cjs coerces the user-influenced size parameter to a signed 32-bit integer, allowing a value of 2147483648 to become -2147483648 and corrupt the process-wide CSPRNG poolOffset in fillPool(), which causes subsequent session tokens, CSRF tokens, API keys, and unique identifiers to become the deterministic string "uuuuuuuuuuuuuuuuuuuuu" until the process restarts. This issue is fixed in versions 3.3.12 and 5.1.11.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-73086)

Affected packages:

- `nanoid < 3.3.12`
- `nanoid >= 4.0.0, < 5.1.11`

Patched in:

- `nanoid 3.3.12`
- `nanoid 5.1.11`

Source: https://github.com/advisories/GHSA-xwg4-73v4-xw9w