CVE-2026-63439

Full vulnerability record from the local CVENow database.

Description

2FAuth is a web app to manage Two-Factor Authentication (2FA) accounts and generate their security codes. Prior to 8.0.0, when AUTHENTICATION_GUARD=reverse-proxy-guard is enabled, ReverseProxyGuard::user() reads the default REMOTE_USER identity header, or a custom identity header selected by the AUTH_PROXY_HEADER_FOR_USER configuration setting, without confirming that the request originated from a configured trusted proxy. A remote client that can reach the application directly can forge the selected identity header and authenticate as an existing user, including an administrator, gaining access to stored 2FA secrets and account or application management functions. This issue is fixed in version 8.0.0.

Severity

CRITICAL

CVSS score

9.8 (v3.1)

Vulnerability status

Received

Source identifier

[email protected]

Published

2026-11-06 21:17:09.970000

Last modified

2026-11-06 21:17:09.970000

View original CVE JSON

{
  "id": "CVE-2026-63439",
  "sourceIdentifier": "[email protected]",
  "published": "2026-11-06T21:17:09.970",
  "lastModified": "2026-11-06T21:17:09.970",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "2FAuth is a web app to manage Two-Factor Authentication (2FA) accounts and generate their security codes. Prior to 8.0.0, when AUTHENTICATION_GUARD=reverse-proxy-guard is enabled, ReverseProxyGuard::user() reads the default REMOTE_USER identity header, or a custom identity header selected by the AUTH_PROXY_HEADER_FOR_USER configuration setting, without confirming that the request originated from a configured trusted proxy. A remote client that can reach the application directly can forge the selected identity header and authenticate as an existing user, including an administrator, gaining access to stored 2FA secrets and account or application management functions. This issue is fixed in version 8.0.0."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Bubka",
          "product": "2FAuth",
          "versions": [
            {
              "version": "< 8.0.0",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/Bubka/2FAuth/commit/43873cbfba445926c7008b4291eeee67752af9e8",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/Bubka/2FAuth/releases/tag/v8.0.0",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/Bubka/2FAuth/security/advisories/GHSA-mh8r-74x2-r457",
      "source": "[email protected]"
    }
  ]
}