CVE-2026-77560

8.1 HIGHpublic exploit available

Published 2026-09-21 · Updated 2026-09-24

AI risk analysis

Summary: The flaw in Tinyauth allows an authenticated low-privilege user to bypass per-app access controls by using a differently cased hostname, leading to unauthorized access to restricted applications.
Exploitability: Exploitation is relatively easy given the preconditions of an authenticated low-privilege user and a misconfigured reverse proxy.
Blast radius: If exploited, this could result in unauthorized access to sensitive applications and data, potentially leading to data breaches or other security incidents.
Detection: No reliable host or network indicator is derivable from the published description.
Prioritized remediation: Upgrade to Tinyauth version 5.1.2 or later.

auth-bypasswebmisconfigurationaccess-control

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD description

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Weaknesses

CWE-178, CWE-636, CWE-863

Public exploit & PoC references

References

Data: NVD (public domain). Analysis: local $0 model. Defensive use only.