# Vault username enumeration

Source: https://startwithidentity.com/cves/cve-2025-6010/
Last updated: 2026-08-29
License: content by Start with Identity. Cite the source URL.

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## What broke

Vault returned a different error (or timing) for "user does not exist" and "wrong password." That is username enumeration. Fixed in 1.20.2. A sibling timing side-channel is [CVE-2025-6011](https://startwithidentity.com/cves/cve-2025-6011/).

## Why it matters

Enumeration is how the [lockout bypass](https://startwithidentity.com/cves/cve-2025-6004/) becomes a targeted brute force instead of a noisy spray. On a human-reachable Vault UI this is worth patching even if the score looks medium.

## What to do

- Upgrade. Confirm login errors are identical for unknown and known users.
- Put the UI behind SSO. Do not offer Userpass on the internet.

## After you patch

A vault compromise is not one credential, it is every credential the vault held or could issue.

- **Rotate everything in scope**, including secrets the vault issued dynamically during the exposure window, because a lease that was valid then may still be valid now.
- **Revoke active leases and tokens**, then review the audit device log for reads you cannot attribute to a known workload.
- **Rotate the vault's own credentials**: unseal or recovery keys, root tokens, and any authentication backend configuration that could be used to re-enter.
- **Rotate downstream credentials the vault brokered**, cloud roles, database users, and PKI certificates, since the point of the vault is that it can mint them. See [secrets rotation](https://startwithidentity.com/glossary/secrets-rotation/) and [what is secrets management](https://startwithidentity.com/guides/fundamentals/what-is-secrets-management/).

## Sources

- [NVD: CVE-2025-6010](https://nvd.nist.gov/vuln/detail/CVE-2025-6010)