Vulnerability Description
Kyoo is a self-hosted media server focused on movies, series, and anime. Prior to 5.1.0, an unauthenticated attacker could initiate the OIDC login flow with an attacker-controlled redirectUrl. The login handling in auth/oidc.go stored that URL with the opaque login state, and /auth/oidc/logged/{provider} appended the provider, token, and error values before redirecting the victim's browser without validating the destination. Because the one-use token was not bound to the browser session that initiated login, an attacker who induced a victim to complete OIDC authentication could capture the token at the attacker-controlled destination and exchange it through /auth/oidc/callback/{provider} for the victim's Kyoo session. This issue is fixed in version 5.1.0.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/zoriya/Kyoo/commit/02ab3af8127a081295fd7bed103847173c0d7632
- https://github.com/zoriya/Kyoo/pull/1576
- https://github.com/zoriya/Kyoo/releases/tag/v5.1.0
- https://github.com/zoriya/Kyoo/security/advisories/GHSA-xhg6-v78p-xf44
FAQ
What is CVE-2026-77386?
CVE-2026-77386 is a vulnerability with a CVSS score of 6.5 (MEDIUM). Kyoo is a self-hosted media server focused on movies, series, and anime. Prior to 5.1.0, an unauthenticated attacker could initiate the OIDC login flow with an attacker-controlled redirectUrl. The log...
How severe is CVE-2026-77386?
CVE-2026-77386 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-77386?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.