{"id":"GHSA-9r87-mvcw-x35f","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!","aliases":["CVE-2026-55075","GO-2026-5908"],"modified":"2026-07-07T16:11:29.771457166Z","published":"2026-07-06T20:52:13Z","database_specific":{"nvd_published_at":null,"cwe_ids":["CWE-287","CWE-289"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-07-06T20:52:13Z"},"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"}],"affected":[{"package":{"name":"github.com/coder/coder/v2","ecosystem":"Go","purl":"pkg:golang/github.com/coder/coder/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.34.0"},{"fixed":"2.34.2"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-9r87-mvcw-x35f/GHSA-9r87-mvcw-x35f.json"}},{"package":{"name":"github.com/coder/coder/v2","ecosystem":"Go","purl":"pkg:golang/github.com/coder/coder/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.33.0"},{"fixed":"2.33.8"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-9r87-mvcw-x35f/GHSA-9r87-mvcw-x35f.json"}},{"package":{"name":"github.com/coder/coder/v2","ecosystem":"Go","purl":"pkg:golang/github.com/coder/coder/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.30.0"},{"fixed":"2.32.7"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-9r87-mvcw-x35f/GHSA-9r87-mvcw-x35f.json"}},{"package":{"name":"github.com/coder/coder/v2","ecosystem":"Go","purl":"pkg:golang/github.com/coder/coder/v2"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.29.17"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-9r87-mvcw-x35f/GHSA-9r87-mvcw-x35f.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}