Password reuse means one breach anywhere effectively becomes a breach everywhere that password was used — it’s consistently cited as the largest amplifier of breach impact, independent of any single site’s own security.
Why it’s so damaging
- Attackers don’t need to breach your systems at all — they only need one weaker, unrelated site you also used the same password on
- Credential stuffing tools automate testing reused passwords across thousands of sites within minutes of a new breach going public
The fix is simple, if under-adopted
A unique, generated password per account, stored in a password manager, fully eliminates this risk category — it’s one of the highest-leverage, lowest-cost security improvements available to both individuals and organizations.
FAQ
Is it enough to just use strong (but reused) passwords?
No — strength protects against guessing; only uniqueness protects against reuse-based attacks like credential stuffing, and the two are independent properties.