tinyauthapp Tinyauth up to 5.1.1 access_controls_service.go access control

Summaryinfo

A vulnerability was found in tinyauthapp Tinyauth up to 5.1.1. It has been declared as critical. Affected is the function lookupStaticACLs/GetAccessControls/GetLabels/proxyHandler of the file internal/service/access_controls_service.go. Such manipulation leads to access control. This vulnerability is documented as CVE-2026-77560. The attack can be executed remotely. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in tinyauthapp Tinyauth up to 5.1.1. It has been rated as critical. Affected by this issue is the function lookupStaticACLs/GetAccessControls/GetLabels/proxyHandler of the file internal/service/access_controls_service.go. The manipulation with an unknown input leads to a access control vulnerability. Using CWE to declare the problem leads to CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Tinyauth is an authentication and authorization server. Prior to 5.1.2, Tinyauth compares forwarded hostnames case-sensitively while reverse proxies route equivalent hostnames case-insensitively, allowing an authenticated low-privilege user to bypass per-app access controls with a differently cased hostname. The lookup in internal/service/access_controls_service.go through lookupStaticACLs and GetAccessControls, and the Docker-label fallback in internal/service/docker_service.go through GetLabels, can miss the configured app and return an empty access-control object. internal/controller/proxy_controller.go proxyHandler then treats the empty user, group, OAuth, LDAP, and IP restrictions as permissive and returns an authenticated result for an app that should exclude the user. Unauthenticated users remain subject to login, and global login-time allowlists are not bypassed. This issue is fixed in version 5.1.2.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-77560 since 08/20/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1068.

Upgrading to version 5.1.2 eliminates this vulnerability.

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Productinfo

Vendor

• tinyauthapp

Name

• Tinyauth

Version

• 5.1.0
• 5.1.1

Website

• Product: https://github.com/tinyauthapp/tinyauth/

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