{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coder/coder/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.34.0"
            },
            {
              "fixed": "2.34.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coder/coder/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.33.0"
            },
            {
              "fixed": "2.33.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coder/coder/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.30.0"
            },
            {
              "fixed": "2.32.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coder/coder/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.29.17"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-203",
      "CWE-204"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-20T18:34:21Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "### Summary\n\n`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\u0027s login type, versus 401 for password users.\n\n\u003e **Note:** Practical exploitation is limited because the timing side channel is noisy and only reveals whether an account exists.\n\n### Impact\n\nAn 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.\n\n### Patches\n\nThe fix derives the timing-defense placeholder from a secure random value that no supplied password can match.\n\nThe fix was backported to all supported release lines:\n\n| Release line | Patched version |\n|---|---|\n| 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) |\n| 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) |\n| 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) |\n| 2.29 (ESR) | [v2.29.17](https://github.com/coder/coder/releases/tag/v2.29.17) |\n\n### Workarounds\n\nNone.\n\n### References\n\n- Fix: #26205\n\n### Credits\n\nWe\u0027d like to thank Anthropic\u0027s Security Team (ANT-2026-22433) for independently disclosing this issue!",
  "id": "GHSA-8fxq-53rx-ph5f",
  "modified": "2026-08-20T18:34:21Z",
  "published": "2026-08-20T18:34:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/security/advisories/GHSA-8fxq-53rx-ph5f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/pull/26205"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/commit/35a7dc8ab9c7f15ce05d963947823ee31224512f"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/coder/coder"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/releases/tag/v2.29.17"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/releases/tag/v2.32.7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/releases/tag/v2.33.8"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/releases/tag/v2.34.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Coder: Login endpoint user enumeration via timing-defense placeholder in password comparison"
}