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GHSA-44jg-mv3h-wj6g solspace/craft-freeform

GHSA-44jg-mv3h-wj6g is a remote code execution vulnerability in solspace/craft-freeform. A fix is available for solspace/craft-freeform — see the affected versions and patch details below.

solspace/craft-freeform Vulnerable to XSS in `PhpSpreadsheet` HTML Writer Due to Unsanitized Styling Data

Published
Jan 15, 2026
Updated
Feb 3, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Feb 3, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
🐘solspace/craft-freeform

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Summary

Short summary of the problem. Make the impact and severity as clear as possible. For example: An unsafe deserialization vulnerability allows any unauthenticated user to execute arbitrary code on the server.

\PhpOffice\PhpSpreadsheet\Writer\Html doesn't sanitize spreadsheet styling information such as font names, allowing an attacker to inject arbitrary JavaScript on the page.

Details

Give all details on the vulnerability. Pointing to the incriminated source code is very helpful for the maintainer.

See https://github.com/advisories/GHSA-wgmf-q9vr-vww6

PoC

Complete instructions, including specific configuration details, to reproduce the vulnerability.

Example target script:

<?php

require 'vendor/autoload.php';

$reader = \PhpOffice\PhpSpreadsheet\IOFactory::createReader("Xlsx");
$spreadsheet = $reader->load(__DIR__ . '/book.xlsx');

$writer = new \PhpOffice\PhpSpreadsheet\Writer\Html($spreadsheet);
print($writer->generateHTMLAll());

Save this file in the same directory:

book.xlsx

Open index.php in a web browser. An alert should be displayed.

Impact

What kind of vulnerability is it? Who is impacted?

Full takeover of the session of users viewing spreadsheet files as HTML.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistsolspace/craft-freeformall versions4.1.23composer require solspace/craft-freeform:^4.1.23

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for solspace/craft-freeform, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update solspace/craft-freeform to 4.1.23 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-44jg-mv3h-wj6g is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-44jg-mv3h-wj6g can be triaged on real exposure rather than presence alone.

Tailored to GHSA-44jg-mv3h-wj6g. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary _Short summary of the problem. Make the impact and severity as clear as possible. For example: An unsafe deserialization vulnerability allows any unauthenticated user to execute arbitrary code on the server._ \PhpOffice\PhpSpreadsheet\Writer\Html doesn't sanitize spreadsheet styling information such as font names, allowing an attacker to inject arbitrary JavaScript on the page. ### Details _Give all details on the vulnerability. Pointing to the incriminated source code is very helpful for the maintainer._ See https://github.com/advisories/GHSA-wgmf-q9vr-vww6 ### PoC _Complete i
O3 Security · Impact-Aware SCA

Is GHSA-44jg-mv3h-wj6g in your dependencies?

O3 Security finds GHSA-44jg-mv3h-wj6g across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-44jg-mv3h-wj6g: solspace/craft RCE | O3 Security