Medium · published July 29, 2026
nanoid (Nano ID) before 5.1.6 contains an infinite loop in the customAlphabet and customRandom functions. When these functions are configured with a size of 0, the internal generation loop never satisfies its exit condition and spins indefinitely, hanging the calling thread. An application that passes an unvalidated, attacker-controlled size of 0 to these functions is exposed to a denial-of-service condition.
| Product | Versions | Fixed in |
|---|---|---|
| nanoid_project/nanoid | ≥ 3.0.0, < 3.3.17 | 3.3.17 |
| nanoid_project/nanoid | ≥ 5.0.0, < 5.1.6 | 5.1.6 |