nanoid: non-secure generators can loop indefinitely with negative size
nanoid (Nano ID) before 5.1.16 contains an infinite loop in the customAlphabet and nanoid functions of its non-secure module (nanoid/non-secure). When these functions are given a negative size, the loop counter is decremented from a negative value and never reaches its termination condition, spinning indefinitely and hanging the calling thread. An application that passes an unvalidated, attacker-controlled negative size to these functions is exposed to a denial-of-service condition.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | nanoid | < 3.3.16, >= 4.0.0, < 5.1.16 | 3.3.16, 5.1.16 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-67214
- https://github.com/ai/nanoid/pull/600
- https://github.com/ai/nanoid/pull/601
- https://github.com/ai/nanoid/commit/6ccc67bbaba71d3d77a21d9b636f4171a268ce49
- https://github.com/ai/nanoid/commit/e835c9b71eab832bc6106944bdd26ea96cf2c66d
- https://github.com/ai/nanoid
- https://github.com/ai/nanoid/releases/tag/5.1.16
- https://www.vulncheck.com/advisories/nanoid-before-infinite-loop-via-negative-size-in-non-secure-module
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-835- Platform
- npm
- Package
nanoid- Disclosed
- 29.07.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-28wg-ghj8-5hjv - CC BY 4.0
Vulnerability history: nanoid
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 5
- First → latest
- 01.2022 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 3
- Medium 2
Disclosures per year
- 2022: 1
- 2023: 0
- 2024: 1
- 2025: 0
- 2026: 3
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nanoid: non-secure generators can loop indefinitely with negative size this entry
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