Vulnerability · Published Aug 11, 2026 · Assigned by GitHub_M
CVE-2026-73086nanoid: Integer Overflow or Wraparound
High 7.4
In plain English
A high-severity integer overflow in nanoid from ai. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | node-mocha | 9.1.4+ds1+~cs28.2.8-1 | DEBIAN-CVE-2026-73086 |
| Debian:13 | node-mocha | 9.1.4+ds1+~cs28.2.8-1 | DEBIAN-CVE-2026-73086 |
| Debian:14 | node-mocha | 9.1.4+ds1+~cs28.2.8-1 | DEBIAN-CVE-2026-73086 |
| Debian:12 | node-postcss | no fix listed | DEBIAN-CVE-2026-73086 |
| Debian:13 | node-postcss | no fix listed | DEBIAN-CVE-2026-73086 |
| Debian:14 | node-postcss | 8.5.14+~cs9.3.34-1 | DEBIAN-CVE-2026-73086 |
| Ubuntu:22.04:LTS | node-postcss | no fix listed | UBUNTU-CVE-2026-73086 |
| Ubuntu:24.04:LTS | node-postcss | no fix listed | UBUNTU-CVE-2026-73086 |
| Ubuntu:26.04:LTS | node-postcss | no fix listed | UBUNTU-CVE-2026-73086 |
| npm | nanoid | 5.1.11 | GHSA-xwg4-73v4-xw9w |
| npm | nanoid | 3.3.12 | GHSA-xwg4-73v4-xw9w |
Affected products (as reported)
Weakness: CWE-190 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
References
- https://github.com/ai/nanoid/security/advisories/GHSA-xwg4-73v4-xw9w x_refsource_CONFIRM
- https://github.com/ai/nanoid/commit/7087969281cab8ba8ae3babf1894e819068b3bb4 x_refsource_MISC
- https://github.com/ai/nanoid/commit/821dfed7b5db7f88e92f56c60eef32c8135077c3 x_refsource_MISC
- https://github.com/ai/nanoid/commit/b0036ed60dc9facd7f1191a50dfb3076500202ac x_refsource_MISC
- https://github.com/ai/nanoid/releases/tag/3.3.12 x_refsource_MISC
- https://github.com/ai/nanoid/releases/tag/5.1.11 x_refsource_MISC