GHSA-v66g-p9x6-v98p
MEDIUMPhpSpreadsheet has an Unauthenticated Cross-Site-Scripting (XSS) in sample file
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/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
Summary
One of the sample scripts in PhpSpreadsheet is susceptible to a cross-site scripting (XSS) vulnerability due to improper handling of input where a number is expected leading to formula injection.
Details
The following code in 45_Quadratic_equation_solver.php concatenates the user supplied parameters directly into spreadsheet formulas. This allows an attacker to take control over the formula and output unsanitized data into the page, resulting in JavaScript execution.
$discriminantFormula = '=POWER(' . $_POST['B'] . ',2) - (4 * ' . $_POST['A'] . ' * ' . $_POST['C'] . ')';
$discriminant = Calculation::getInstance()->calculateFormula($discriminantFormula);
$r1Formula = '=IMDIV(IMSUM(-' . $_POST['B'] . ',IMSQRT(' . $discriminant . ')),2 * ' . $_POST['A'] . ')';
$r2Formula = '=IF(' . $discriminant . '=0,"Only one root",IMDIV(IMSUB(-' . $_POST['B'] . ',IMSQRT(' . $discriminant . ')),2 * ' . $_POST['A'] . '))';
PoC
- Access
45_Quadratic_equation_solver.phpin a browser - Enter any valid values for for
bandc, and enter the following fora
1) & ("1)),1)&char(60)&char(105)&char(109)&char(103)&char(32)&char(115)&char(114)&char(99)&char(61)&char(120)&char(32)&char(111)&char(110)&char(101)&char(114)&char(114)&char(111)&char(114)&char(61)&char(97)&char(108)&char(101)&char(114)&char(116)&char(40)&char(41)&char(62)&POWER(((1") &n("1")&(1
- Press submit and observe that JavaScript is executed.
Impact
The impact of this vulnerability on the project is expected to be relatively low since these are sample files that should not be included when the library is used properly (e.g., through composer). However, at least two instances of popular WordPress plugins have unintentionally exposed this file by including the entire git repository. Since these files also serve as reference points for developers using the library, addressing this issue can enhance security for users.
A solution to fix the vulnerability is proposed below, and a request for a CVE assignment has been made to facilitate responsible disclosure of the security issue to the affected WordPress plugins.
Remediation
A quick and easy solution to prevent this attack is to force the parameters to be numerical values:
if (isset($_POST['submit'])) {
$_POST['A'] = floatval($_POST['A']);
$_POST['B'] = floatval($_POST['B']);
$_POST['C'] = floatval($_POST['C']);
if ($_POST['A'] == 0) {
Thank you for your time!
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | phpoffice/phpspreadsheet | ≥ 2.2.0&&< 2.3.0 | 2.3.0 |
| 🐘Packagist | phpoffice/phpspreadsheet | all versions | 1.29.2 |
| 🐘Packagist | phpoffice/phpspreadsheet | ≥ 2.0.0&&< 2.1.1 | 2.1.1 |
| 🐘Packagist | phpoffice/phpexcel | all versions | No fix |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
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 2.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v66g-p9x6-v98p 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-v66g-p9x6-v98p 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-v66g-p9x6-v98p. 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-v66g-p9x6-v98p in your dependencies?
O3 detects GHSA-v66g-p9x6-v98p across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.