GHSA-jmpx-686v-c3wx
HIGHPhpSpreadsheet allows unauthorized Reflected XSS in the constructor of the Downloader class
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
phpoffice/phpspreadsheet🐘phpoffice/phpspreadsheet🐘phpoffice/phpspreadsheet🐘phpoffice/phpspreadsheet🐘phpoffice/phpexcelReal-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
Unauthorized Reflected XSS in the constructor of the Downloader class
Product: Phpspreadsheet
Version: version 3.6.0
CWE-ID: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSS vector v.3.1: 8.2 (AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N)
CVSS vector v.4.0: 8.3 (AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:L/SI:H/SA:L)
Description: using the /vendor/phpoffice/phpspreadsheet/samples/download.php script, an attacker can perform a XSS-type attack
Impact: execution of arbitrary JavaScript code in the browser
Vulnerable component: the constructor of the Downloader class
Exploitation conditions: an unauthorized user
Mitigation: sanitization of the name and type variables
Researcher: Aleksey Solovev (Positive Technologies)
Research
The researcher discovered zero-day vulnerability Unauthorized Reflected Cross-Site Scripting (XSS) (in the constructor of the Downloader class) in Phpspreadsheet.
The latest version (3.6.0) of the phpoffice/phpspreadsheet library was installed. The installation was carried out with the inclusion of examples.
Listing 1. Installing the phpoffice/phpspreadsheet library
$ composer require phpoffice/phpspreadsheet --prefer-source
The ./vendor/phpoffice/phpspreadsheet/samples/download.php file processes the GET parameters name and type.
Figure 1. The ./vendor/phpoffice/phpspreadsheet/samples/download.php file accepts GET parameters.
Consider the constructor of the Downloader class, where GET parameters are passed. Error is displayed without sanitization using GET parameters transmitted from the user.
Figure 2. Error is displayed without sanitization
When clicking on the following link, arbitrary JavaScript code will be executed.
Listing 2.
https://192.***.***.***/vendor/phpoffice/phpspreadsheet/samples/download.php?name=%3Cimg%20src=1%20onerror=alert()%3E&type=1
Demonstration of the execution of arbitrary JavaScript code.
<img width="537" alt="fig3" src="https://github.com/user-attachments/assets/745d6e21-396f-4357-8ff8-e856adf15fee" />Figure 3. Executing arbitrary JavaScript code
Credit
This vulnerability was discovered by Aleksey Solovev (Positive Technologies)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | phpoffice/phpspreadsheet | ≥ 3.0.0&&< 3.7.0 | 3.7.0 |
| 🐘Packagist | phpoffice/phpspreadsheet | all versions | 1.29.7 |
| 🐘Packagist | phpoffice/phpspreadsheet | ≥ 2.0.0&&< 2.1.6 | 2.1.6 |
| 🐘Packagist | phpoffice/phpspreadsheet | ≥ 2.2.0&&< 2.3.5 | 2.3.5 |
| 🐘Packagist | phpoffice/phpexcel | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for phpoffice/phpspreadsheet. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update phpoffice/phpspreadsheet to 3.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-jmpx-686v-c3wx is resolved across your whole dependency graph.
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.
How O3 protects you
O3 pinpoints whether GHSA-jmpx-686v-c3wx is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-jmpx-686v-c3wx. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-jmpx-686v-c3wx in your dependencies?
O3 detects GHSA-jmpx-686v-c3wx across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.