How severe is CVE-2024-56412?

No CVSS score has been assigned to CVE-2024-56412 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2024-56412?

CVE-2024-56412 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 CVE-2024-56412?

Update phpoffice/phpspreadsheet to 3.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-56412 is resolved across your whole dependency graph.

How do I detect CVE-2024-56412 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 CVE-2024-56412 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 CVE-2024-56412?

O3 pinpoints whether CVE-2024-56412 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 CVE-2024-56412 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-56412 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 type of vulnerability is CVE-2024-56412?

CVE-2024-56412 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 CVE-2024-56412 published, and has it been updated?

CVE-2024-56412 was published on January 3, 2025 and was last updated on August 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2024-56412

Fix: PHPOffice/PhpSpreadsheet@45052f8

CVE-2024-56412 is a Cross-site Scripting (XSS) vulnerability in phpoffice/phpspreadsheet. O3 Security confirms whether CVE-2024-56412 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

PhpSpreadsheet vulnerable to bypass of the XSS sanitizer using the javascript protocol and special characters

Also known asGHSA-q9jv-mm3r-j47r

Published

Jan 3, 2025

Updated

Aug 8, 2026

Affected

5 pkgs

Patched

4 / 5

Exploits

None indexed

Exploitation data as of Aug 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

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

PhpSpreadsheet is a PHP library for reading and writing spreadsheet files. Versions prior to 3.7.0, 2.3.5, 2.1.6, and 1.29.7 are vulnerable to bypass of the cross-site scripting sanitizer using the javascript protocol and special characters. An attacker can use special characters, so that the library processes the javascript protocol with special characters and generates an HTML link. Versions 3.7.0, 2.3.5, 2.1.6, and 1.29.7 contain a patch for the issue.

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 CVE-2024-56412 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 CVE-2024-56412 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 CVE-2024-56412. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2024-56412 in your dependencies?

O3 detects CVE-2024-56412 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