Deserialization of Untrusted Data Affecting phpoffice/phpspreadsheet package, versions <1.30.5>=2.0.0, <2.1.17>=2.2.0, <2.4.6>=3.3.0, <3.10.6>=4.0.0, <5.8.0
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-PHP-PHPOFFICEPHPSPREADSHEET-17420061
- published23 Jun 2026
- disclosed22 Jun 2026
- crediteverping
Introduced: 22 Jun 2026
CVE-2026-45034 (opens in a new tab)How to fix?
Upgrade phpoffice/phpspreadsheet to version 1.30.5, 2.1.17, 2.4.6, 3.10.6, 5.8.0 or higher.
Overview
phpoffice/phpspreadsheet is a Spreadsheet engine that Read, Create and Write Spreadsheet documents in PHP .
Affected versions of this package are vulnerable to Deserialization of Untrusted Data in the File::prohibitWrappers() function. An attacker can execute arbitrary code or read files by supplying a specially crafted path containing a stream wrapper such as phar:///, which bypasses the intended security check and leads to unsafe deserialization or file access.
Note:
This issue is due to incomplete fix for CVE-2026-34084. This bypass directly affects 1.30.x version line, later versions can allow RCE if the downstream consumer calls Phar::getMetadata.
Details
Serialization is a process of converting an object into a sequence of bytes which can be persisted to a disk or database or can be sent through streams. The reverse process of creating object from sequence of bytes is called deserialization. Serialization is commonly used for communication (sharing objects between multiple hosts) and persistence (store the object state in a file or a database). It is an integral part of popular protocols like Remote Method Invocation (RMI), Java Management Extension (JMX), Java Messaging System (JMS), Action Message Format (AMF), Java Server Faces (JSF) ViewState, etc.
Deserialization of untrusted data (CWE-502) is when the application deserializes untrusted data without sufficiently verifying that the resulting data will be valid, thus allowing the attacker to control the state or the flow of the execution.