Junglewise Threat Intelligence

CVE-2026-55075: Coder account takeover via OIDC authentication bypass

CVE-2026-55075 · Severity: high · CVSS 7.4 · Published 2026-07-07

Technologies: Coder. Vendors: Go, Coder.

Executive brief

Coder, a platform for managing remote development environments, contains a security flaw in its login system that could allow an attacker to take over user accounts. By exploiting how the system verifies email addresses and links them to external login providers (like Google or Microsoft), an attacker could trick the platform into granting them access to a victim's workspace. This could lead to the theft of sensitive source code or unauthorized access to corporate development infrastructure.

Technical details

Two vulnerabilities in Coder's OIDC implementation can be chained to achieve account takeover. First, the `email_verified` claim check used a Go type assertion that failed silently if the claim was a string, number, or absent, defaulting to 'verified'. Second, the `findLinkedUser` function performed an email-based lookup fallback for all logins without verifying if the email was already linked to a different Identity Provider (IdP) subject. An attacker can register a victim's email at an IdP and bypass the `linked_id` check to match the victim's Coder account. The fix restricts email fallback to first-time linking and implements fail-closed logic for the `email_verified` claim.

Affected products

  • Coder Coder < 2.29.17, >= 2.30.0 < 2.32.7, >= 2.33.0 < 2.33.8, >= 2.34.0 < 2.34.2

Timeline

  • 2026-05-27: other: Internal fixes submitted via pull requests
  • 2026-06-12: patched: Security hardening releases published
  • 2026-07-07: disclosed: CVE published to NVD

References

Related threats