GHSA-75vm-6w67-gwvp Coder's OIDC email_verified type coercion bypass enables account takeover via unverified email linking

• Go github.com/coder/coder/v2: >= 2.34.0, < 2.34.2 → fixed in 2.34.2 • Go github.com/coder/coder/v2: >= 2.33.0, < 2.33.8 → fixed in 2.33.8 • Go github.com/coder/coder/v2: >= 2.30.0, < 2.32.7 → fixed in 2.32.7 • Go github.com/coder/coder/v2: < 2.29.17 → fixed in 2.29.17

Summary Coder'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. Impact An 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. Patches The 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. The fix was backported to all supported release lines: | Release line | Patched version | |---|---| | 2.34 | v2.34.2 | | 2.33 | v2.33.8 | | 2.32 | v2.32.7 | | 2.29 (ESR) | v2.29.17 | Workarounds Ensure the IdP returns `email_verified` as a native JSON boolean. The email-fallback linking issue has no configuration workaround; upgrading is required. Resources • Fix: #25712, #25713 Credits Coder would like to thank Anthropic's Security Team (ANT-2026-22444) for independently disclosing this issue!