{"id":"CVE-2026-55076","aliases":["GHSA-75vm-6w67-gwvp"],"title":"Coder's OIDC email_verified type coercion bypass enables account takeover via unverified email linking","summary":"Coder's OIDC email_verified type coercion bypass enables account takeover via unverified email linking","severity":"high","cvss":7.4,"cwe":["CWE-287","CWE-704"],"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":"2026-07-06","updated":"2026-07-06","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-75vm-6w67-gwvp","references":[{"url":"https://github.com/coder/coder/security/advisories/GHSA-75vm-6w67-gwvp"},{"url":"https://github.com/advisories/GHSA-75vm-6w67-gwvp"}],"tags":["ghsa","go"],"ingestedAt":"2026-07-06T21:45:52.980Z","epss":0.0061,"epssPercentile":0.47576,"slug":"CVE-2026-55076","body":"## Overview\n\n### Summary\n\nCoder's OIDC callback checked `email_verified` with a direct Go `bool` type assertion. When an IdP returned the claim as a non-boolean (for example the string `\"false\"`) or omitted it, the assertion failed open and the email was treated as verified. Combined with an unconditional email-based account fallback, this enabled account takeover.\n\n### Impact\n\nAn attacker who registered a victim's email at a compatible IdP without verifying it could log in via OIDC and be matched to the victim's existing Coder account, receiving a session for that account. No prior authentication to Coder was required and the result was full account takeover.\n\n### Patches\n\nThe fix coerces `email_verified` across bool, string and numeric types (fail-closed) and blocks the email fallback when the matched user already has a different linked IdP subject.\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\nEnsure the IdP returns `email_verified` as a native JSON boolean. The email-fallback linking issue has no configuration workaround; upgrading is required.\n\n### Resources\n\n- Fix: #25712, #25713\n\n### Credits\n\nCoder would like to thank Anthropic's Security Team (ANT-2026-22444) for independently disclosing this issue!\n\n## Affected packages\n\n- `github.com/coder/coder/v2 >= 2.34.0, < 2.34.2`\n- `github.com/coder/coder/v2 >= 2.33.0, < 2.33.8`\n- `github.com/coder/coder/v2 >= 2.30.0, < 2.32.7`\n- `github.com/coder/coder/v2 < 2.29.17`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `github.com/coder/coder/v2 2.34.2`\n- `github.com/coder/coder/v2 2.33.8`\n- `github.com/coder/coder/v2 2.32.7`\n- `github.com/coder/coder/v2 2.29.17`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":40.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}