CVE-2024-56412: PhpSpreadsheet vulnerable to bypass of the XSS sanitizer using the javascript protocol and special characters

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2025-01-03 · updated 2026-06-17
Weakness: CWE-79

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 products

PHPOffice PhpSpreadsheet: before 1.29.7; from 2.0.0 before 2.1.6; from 2.2.0 before 2.3.5; from 3.0.0 before 3.7.0 — fixed in 1.29.7, 2.1.6, 2.3.5, 3.7.0

How to fix

Upgrade to a fixed version: PHPOffice PhpSpreadsheet 1.29.7, 2.1.6, 2.3.5, 3.7.0. Check the vendor advisory for mitigations.

References

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