FKIE_CVE-2026-77560

Vulnerability from fkie_nvd - Published: 2026-09-21 17:18 - Updated: 2026-09-21 21:17
Severity
8.1 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
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 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.
References
security-advisories@github.comhttps://github.com/tinyauthapp/tinyauth/commit/80bc87188ec3aabc5104c249eaa7b997973b9275
security-advisories@github.comhttps://github.com/tinyauthapp/tinyauth/commit/e75605b2c534ec83525a33603e16d76baca13399
security-advisories@github.comhttps://github.com/tinyauthapp/tinyauth/pull/1000
security-advisories@github.comhttps://github.com/tinyauthapp/tinyauth/pull/1028
security-advisories@github.comhttps://github.com/tinyauthapp/tinyauth/releases/tag/v5.1.2
security-advisories@github.comhttps://github.com/tinyauthapp/tinyauth/security/advisories/GHSA-328g-jx67-v94g
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "tinyauth",
          "vendor": "tinyauthapp",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 5.1.2"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "id": "CVE-2026-77560",
  "lastModified": "2026-09-21T21:17:11.637",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.2,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-77560",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-21T20:05:46.154613Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-21T17:18:52.770",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/tinyauthapp/tinyauth/commit/80bc87188ec3aabc5104c249eaa7b997973b9275"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/tinyauthapp/tinyauth/commit/e75605b2c534ec83525a33603e16d76baca13399"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/tinyauthapp/tinyauth/pull/1000"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/tinyauthapp/tinyauth/pull/1028"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/tinyauthapp/tinyauth/releases/tag/v5.1.2"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/tinyauthapp/tinyauth/security/advisories/GHSA-328g-jx67-v94g"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-178"
        },
        {
          "lang": "en",
          "value": "CWE-636"
        },
        {
          "lang": "en",
          "value": "CWE-863"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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