---
id: CVE-2026-77560
title: Tinyauth is an authentication and authorization server
summary: >-
  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 u…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-178
  - CWE-636
  - CWE-863
vendor: tinyauthapp
product: tinyauth
affected:
  - tinyauth < 5.1.2
patched:
  - github.com/tinyauthapp/tinyauth 1.0.1-0.20260720133915-80bc87188ec3
published: '2026-09-21'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T21:25:27.050'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77560'
references:
  - url: >-
      https://github.com/tinyauthapp/tinyauth/commit/80bc87188ec3aabc5104c249eaa7b997973b9275
    label: security-advisories@github.com
  - url: >-
      https://github.com/tinyauthapp/tinyauth/commit/e75605b2c534ec83525a33603e16d76baca13399
    label: security-advisories@github.com
  - url: 'https://github.com/tinyauthapp/tinyauth/pull/1000'
    label: security-advisories@github.com
  - url: 'https://github.com/tinyauthapp/tinyauth/pull/1028'
    label: security-advisories@github.com
  - url: 'https://github.com/tinyauthapp/tinyauth/releases/tag/v5.1.2'
    label: security-advisories@github.com
  - url: >-
      https://github.com/tinyauthapp/tinyauth/security/advisories/GHSA-328g-jx67-v94g
    label: security-advisories@github.com
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77560'
  - url: 'https://github.com/advisories/GHSA-328g-jx67-v94g'
  - url: 'https://github.com/tinyauthapp/tinyauth'
tags:
  - nvd
  - cve.org
  - ghsa
  - go
  - osv
epss: 0.00612
epssPercentile: 0.47018
aliases:
  - GHSA-328g-jx67-v94g
ecosystem: go
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-21T20:05:46.154613Z'
ingestedAt: '2026-09-21T16:49:07.864Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-77560)

Affected packages:

- `github.com/tinyauthapp/tinyauth < 1.0.1-0.20260720133915-80bc87188ec3`

Patched in:

- `github.com/tinyauthapp/tinyauth 1.0.1-0.20260720133915-80bc87188ec3`

Source: https://github.com/advisories/GHSA-328g-jx67-v94g