CVE-2026-55075: Github.com/coder/coder/v2 Coder Vulnerable To OIDC Account Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9r87-mvcw-x35f",
  "modified" : "2026-07-06T20:52:13Z",
  "published" : "2026-07-06T20:52:13Z",
  "aliases" : [ "CVE-2026-55075" ],
  "summary" : "Coder vulnerable to OIDC account takeover via email-based user matching and email_verified bypass",
  "details" : "### Summary\n\nTwo flaws in Coder's OIDC login chained into account takeover: email-based user matching fell back to linking by email without checking for an existing link to a different IdP subject and the `email_verified` claim was only enforced when present as a boolean `false` so an absent or non-boolean claim was treated as verified.\n\n### Impact\n\nAn attacker who could authenticate at the configured OIDC provider with an email matching a victim's Coder account could log in as that victim and gain full access to their workspaces, templates and resources. This required OIDC authentication, attacker control of a matching email at the IdP and a victim account not yet linked to a different IdP subject.\n\n### Patches\n\nThe fix restricts the email fallback to first-time and legacy linking and defaults `email_verified` to false when the claim is absent or of an unexpected type.\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\nConfigure the OIDC provider to disallow self-registration or to require email verification before issuing tokens.\n\n### Resources\n\n- Fix: #25712, #25713\n\n### Credits\n\nCoder would like to thank Anthropic's Security Team (ANT-2026-22450) for independently disclosing this issue!",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/coder/coder/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.34.0"
      }, {
        "fixed" : "2.34.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/coder/coder/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.33.0"
      }, {
        "fixed" : "2.33.8"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/coder/coder/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.30.0"
      }, {
        "fixed" : "2.32.7"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/coder/coder/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.29.17"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/coder/coder/security/advisories/GHSA-9r87-mvcw-x35f"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/coder/coder/pull/25712"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/coder/coder/pull/25713"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/coder/coder"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-287", "CWE-289" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-06T20:52:13Z",
    "nvd_published_at" : null
  }
}