---
id: GHSA-8fxq-53rx-ph5f
title: >-
  Coder: Login endpoint user enumeration via timing-defense placeholder in
  password comparison
summary: >-
  Coder: Login endpoint user enumeration via timing-defense placeholder in
  password comparison
severity: low
cvss: 3.7
cwe:
  - CWE-203
  - CWE-204
vendor: coder
product: github.com/coder/coder/v2
ecosystem: go
affected:
  - 'github.com/coder/coder/v2 >= 2.34.0, < 2.34.2'
  - 'github.com/coder/coder/v2 >= 2.33.0, < 2.33.8'
  - 'github.com/coder/coder/v2 >= 2.30.0, < 2.32.7'
  - github.com/coder/coder/v2 < 2.29.17
patched:
  - github.com/coder/coder/v2 2.34.2
  - github.com/coder/coder/v2 2.33.8
  - github.com/coder/coder/v2 2.32.7
  - github.com/coder/coder/v2 2.29.17
published: '2026-08-20'
updated: '2026-08-20'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-8fxq-53rx-ph5f'
references:
  - url: 'https://github.com/coder/coder/security/advisories/GHSA-8fxq-53rx-ph5f'
  - url: 'https://github.com/coder/coder/pull/26205'
  - url: >-
      https://github.com/coder/coder/commit/35a7dc8ab9c7f15ce05d963947823ee31224512f
  - url: 'https://github.com/coder/coder/releases/tag/v2.29.17'
  - url: 'https://github.com/coder/coder/releases/tag/v2.32.7'
  - url: 'https://github.com/coder/coder/releases/tag/v2.33.8'
  - url: 'https://github.com/coder/coder/releases/tag/v2.34.2'
  - url: 'https://github.com/advisories/GHSA-8fxq-53rx-ph5f'
tags:
  - ghsa
  - go
ingestedAt: '2026-08-20T18:59:55.296Z'
---

## Overview

### Summary

`userpassword.Compare()` substituted a placeholder hash derived from the well-known string `"hunter2"` when the stored hash was empty. Submitting `"hunter2"` therefore matched accounts with no password hash (nonexistent users and SSO-only users) and a subsequent login-type check returned an HTTP 403 that disclosed the account's login type, versus 401 for password users.

> **Note:** Practical exploitation is limited because the timing side channel is noisy and only reveals whether an account exists.

### Impact

An unauthenticated attacker could enumerate valid accounts and their authentication provider by submitting logins with the password `"hunter2"`, distinguishing nonexistent users, SSO users (provider revealed) and password users from the response. This aids credential-stuffing and targeted phishing. No authentication bypass or data access resulted.

### Patches

The fix derives the timing-defense placeholder from a secure random value that no supplied password can match.

The fix was backported to all supported release lines:

| Release line | Patched version |
|---|---|
| 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) |
| 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) |
| 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) |
| 2.29 (ESR) | [v2.29.17](https://github.com/coder/coder/releases/tag/v2.29.17) |

### Workarounds

None.

### References

- Fix: #26205

### Credits

We'd like to thank Anthropic's Security Team (ANT-2026-22433) for independently disclosing this issue!

## Affected packages

- `github.com/coder/coder/v2 >= 2.34.0, < 2.34.2`
- `github.com/coder/coder/v2 >= 2.33.0, < 2.33.8`
- `github.com/coder/coder/v2 >= 2.30.0, < 2.32.7`
- `github.com/coder/coder/v2 < 2.29.17`

## Remediation

Upgrade to a patched release:

- `github.com/coder/coder/v2 2.34.2`
- `github.com/coder/coder/v2 2.33.8`
- `github.com/coder/coder/v2 2.32.7`
- `github.com/coder/coder/v2 2.29.17`