Описание
Coder vulnerable to OIDC account takeover via email-based user matching and email_verified bypass
Summary
Two 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.
Impact
An 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.
Patches
The 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.
The fix was backported to all supported release lines:
Workarounds
Configure the OIDC provider to disallow self-registration or to require email verification before issuing tokens.
Resources
- Fix: #25712, #25713
Credits
Coder would like to thank Anthropic's Security Team (ANT-2026-22450) for independently disclosing this issue!
Пакеты
github.com/coder/coder/v2
>= 2.34.0, < 2.34.2
2.34.2
github.com/coder/coder/v2
>= 2.33.0, < 2.33.8
2.33.8
github.com/coder/coder/v2
>= 2.30.0, < 2.32.7
2.32.7
github.com/coder/coder/v2
< 2.29.17
2.29.17
Связанные уязвимости
Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, two 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. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 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. As a workaround, configure the OIDC provider to disallow self-registration or to require email verification before issuing tokens.