GHSA-pwh2-fpfr-x5gf CVE-2024-28105

phpMyFAQ's File Upload Bypass at Category Image Leads to RCE

High Packagist

Severity: 7.2 / 10; High · CVSS 3.1
Exploit chance (EPSS): 1.48%; Chance of exploitation in the next 30 days. Higher than 73.86% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-434 Unrestricted Upload of File with Dangerous Type
Fix: 3.2.6; Upgrade phpmyfaq/phpmyfaq to this version or later

Description

Summary

The category image upload function in phpmyfaq is vulnerable to manipulation of the Content-type and lang parameters, allowing attackers to upload malicious files with a .php extension, potentially leading to remote code execution (RCE) on the system.

Details

In the file upload function of the category image, the Content-type can be manipulated to return an empty string for the extension and the lang parameter can be set to .php. to allow an attacker to save a file as .PHP. This allows the uploading of web shells which could lead to RCE on phpmyfaq.

PoC

Generate a fake .GIF file that contains a php command using the tool gifsicle a. Cmd: gifsicle < test1.gif --comment "<?php system('whoami'); ?>" > output.php.gif

image

b. The contents of the file should look like this:
image
Browse to “../phpmyfaq/admin/?action=addcategory” and upload the fake .GIF file image
Intercept the upload request and modify the params below and forward it: 3a. lang parameter to .php. 3b. Content-Type parameter from image/gif to image/gif2

image
Browse to the “/phpmyfaq/images” directory and notice that our fake .GIF file has been uploaded as a PHP file with the category number as its filename. image
Now we just need to browse to “../phpmyfaq/images/category-<ID>-.php” and see the results of our whoami command. Hence, verifying that RCE is achieved. image

Impact

Attackers can upload malicious files containing executable code, allowing them to take control of the vulnerable system. This enables them to execute arbitrary commands, steal sensitive data, disrupt services, and potentially escalate their privileges, posing significant risks to the security and integrity of the system and its data.

Occurrences

In CategoryImage.php line 124, the getimagesize and isValidMimeType functions can be bypassed by uploading a fake .GIF file generated by gifsicle.
image

In CategoryImage.php line 85, the getFileExtension function returns an empty string when the content type doesnt match any of the following 3 mappings. Hence, its possible to just supply an invalid content type such as image/gif2 in step 3 of the PoC to make the function return an empty string. image

In CategoryImage.php line 66, the getFileName function generate the filename by concatenating the categoryId, categoryName and fileExtension together. This allows us to save the file with a .PHP extension. (It should be possible to just set the payload in step 3 above to just .php but it doesnt work and im not sure why..) image

Suggested Fix

I believe one of the ways to solve this vulnerability is by forcing the getFileExtension function to return one of the 3 mimetype instead of an empty string. This ensures that the uploaded file will have an image extension and will not execute as a PHP file.

Affected versions

Packagist

Package	Vulnerable	Fixed in
phpmyfaq/phpmyfaq	`>= 3.2.5, < 3.2.6`	`3.2.6`

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.

phpmyfaq/phpmyfaq Packagist → `3.2.6`

composer

composer require phpmyfaq/phpmyfaq:^3.2.6

Severity breakdown

CVSS 3.1 7.2

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Attack vector: Network
Attack complexity: Low
Privileges required: High
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

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

nvd.nist.gov/vuln/detail/CVE-2024-28105

Packages

github.com/thorsten/phpMyFAQ

Timeline

Mar 25, 2024 Published
Sep 10, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-rw77-vq4g-x3hp phpMyFAQ has SQL Injection in `StopWords::add()` — Unescaped Stop Word Insertion	High	Also affects phpmyfaq/phpmyfaq
GHSA-8gpw-xvpf-hvx5 phpMyFAQ's two-factor authentication login bypasses the password factor	High	Also affects phpmyfaq/phpmyfaq
GHSA-pgwp-vc7q-cvj3 phpMyFAQ has Stored XSS in Admin FAQ Editor via HTML Entity Bypass in Frontend FAQ Submission	High	Also affects phpmyfaq/phpmyfaq
GHSA-mf8r-wm2w-f8c5 phpMyFAQ public FAQ APIs expose inactive FAQ content	Medium	Also affects phpmyfaq/phpmyfaq
GHSA-88g4-74f3-63x9 phpMyFAQ has Potential Authenticated Path Traversal in PDF Export	Medium	Also affects phpmyfaq/phpmyfaq
GHSA-pg62-f8g4-4wqh phpMyFAQ privilege escalation: GroupController::updatePermissions lets a GROUP_EDIT admin grant rights they do not hold	High	Also affects phpmyfaq/phpmyfaq
GHSA-985r-q3qp-299h phpMyFAQ has an incomplete fix for GHSA-xvp4-phqj-cjr3 — editUser() and updateUserRights() lack authorization guards	High	Also affects phpmyfaq/phpmyfaq
GHSA-8c6h-7g6x-m5x4 phpMyFAQ: Missing userHasPermission() in 4 API write endpoints (CVE-2026-24421 Incomplete Fix)	Medium	Also affects phpmyfaq/phpmyfaq

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