Coder: Login endpoint user enumeration via timing-defense placeholder in password comparison

{
  "id": "01dacb5a271aae4063c9015476bbc86cc95cd68811391391d3c6c902d76650cd",
  "url": "https://osv.dev/vulnerability/GHSA-8fxq-53rx-ph5f",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Coder: Login endpoint user enumeration via timing-defense placeholder in password comparison",
    "summary": "### 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 Se",
    "evidence": "osv:GHSA-8fxq-53rx-ph5f",
    "products": [
      {
        "name": {
          "value": "github.com/coder/coder/v2",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.34.2",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "github.com/coder/coder/v2",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.33.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "github.com/coder/coder/v2",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.32.7",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "github.com/coder/coder/v2",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.29.17",
            "evidence": "/affected/3/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "low",
    "structured": {
      "id": "GHSA-8fxq-53rx-ph5f",
      "aliases": [
        "CVE-2026-111933",
        "GHSA-8fxq-53rx-ph5f",
        "GO-2026-6265"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "2.34.0"
                },
                {
                  "fixed": "2.34.2"
                }
              ]
            }
          ],
          "package": {
            "name": "github.com/coder/coder/v2",
            "purl": "pkg:golang/github.com/coder/coder/v2",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-8fxq-53rx-ph5f/GHSA-8fxq-53rx-ph5f.json"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "2.33.0"
                },
                {
                  "fixed": "2.33.8"
                }
              ]
            }
          ],
          "package": {
            "name": "github.com/coder/coder/v2",
            "purl": "pkg:golang/github.com/coder/coder/v2",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-8fxq-53rx-ph5f/GHSA-8fxq-53rx-ph5f.json"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "2.30.0"
                },
                {
                  "fixed": "2.32.7"
                }
              ]
            }
          ],
          "package": {
            "name": "github.com/coder/coder/v2",
            "purl": "pkg:golang/github.com/coder/coder/v2",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-8fxq-53rx-ph5f/GHSA-8fxq-53rx-ph5f.json"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.29.17"
                }
              ]
            }
          ],
          "package": {
            "name": "github.com/coder/coder/v2",
            "purl": "pkg:golang/github.com/coder/coder/v2",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-8fxq-53rx-ph5f/GHSA-8fxq-53rx-ph5f.json"
          }
        }
      ],
      "modified": "2026-10-18T10:55:40.994398805Z",
      "provider": "osv",
      "references": [
        "https://github.com/coder/coder/security/advisories/GHSA-8fxq-53rx-ph5f",
        "https://github.com/coder/coder/pull/26205",
        "https://github.com/coder/coder/commit/35a7dc8ab9c7f15ce05d963947823ee31224512f",
        "https://github.com/coder/coder",
        "https://github.com/coder/coder/releases/tag/v2.29.17",
        "https://github.com/coder/coder/releases/tag/v2.32.7",
        "https://github.com/coder/coder/releases/tag/v2.33.8",
        "https://github.com/coder/coder/releases/tag/v2.34.2"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-203",
          "CWE-204"
        ],
        "severity": "LOW",
        "github_reviewed": true,
        "nvd_published_at": null,
        "github_reviewed_at": "2026-08-20T18:34:21Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-111933",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 370022,
  "published_at": "2026-08-20T18:34:21+00:00"
}