PHPOffice PhpSpreadsheet up to 5.5.0 IOFactory::load filename deserialization

Summaryinfo

A vulnerability identified as critical has been detected in PHPOffice PhpSpreadsheet up to 1.30.2/2.1.14/2.4.3/3.10.3/5.5.0. Impacted is the function IOFactory::load. The manipulation of the argument filename leads to deserialization. This vulnerability is listed as CVE-2026-34084. The attack may be initiated remotely. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in PHPOffice PhpSpreadsheet up to 1.30.2/2.1.14/2.4.3/3.10.3/5.5.0. It has been rated as critical. This issue affects the function IOFactory::load. The manipulation of the argument filename with an unknown input leads to a deserialization vulnerability. Using CWE to declare the problem leads to CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

PhpSpreadsheet is a library for reading and writing spreadsheet files. In versions 1.30.2 and earlier, 2.0.0 through 2.1.14, 2.2.0 through 2.4.3, 3.3.0 through 3.10.3, and 4.0.0 through 5.5.0, when the filename argument to IOFactory::load() is user-controlled, an attacker can supply a PHP stream wrapper path (such as phar://, ftp://, or ssh2.sftp://) that passes the is_file() check in File::assertFile(). The phar:// wrapper triggers deserialization of the PHAR metadata, which can lead to remote code execution if a suitable gadget chain is available in the application. The ftp:// and ssh2.sftp:// wrappers can be used for server-side request forgery. This issue has been fixed in versions 1.30.3, 2.1.15, 2.4.4, 3.10.4, and 5.6.0.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-34084 since 03/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 1.30.3, 2.1.15, 2.4.4, 3.10.4 or 5.6.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-27454). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• PHPOffice

Name

• PhpSpreadsheet

Version

• 1.30.0
• 1.30.1
• 1.30.2
• 2.1.0
• 2.1.1
• 2.1.2
• 2.1.3
• 2.1.4
• 2.1.5
• 2.1.6
• 2.1.7
• 2.1.8
• 2.1.9
• 2.1.10
• 2.1.11
• 2.1.12
• 2.1.13
• 2.1.14
• 2.4.0
• 2.4.1
• 2.4.2
• 2.4.3
• 3.10.0
• 3.10.1
• 3.10.2
• 3.10.3
• 5.0
• 5.1
• 5.2
• 5.3
• 5.4
• 5.5.0

Website

• Product: https://github.com/PHPOffice/PhpSpreadsheet/

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Be aware that VulDB is the high quality source for vulnerability data.

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