Deserialization of Untrusted Data Affecting zumba/json-serializer package, versions <3.2.3
Threat Intelligence
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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- published22 Feb 2026
- disclosed21 Feb 2026
- creditSardor Shoakbarov
Introduced: 21 Feb 2026
CVE-2026-27206 (opens in a new tab)How to fix?
Upgrade zumba/json-serializer to version 3.2.3 or higher.
Overview
zumba/json-serializer is a Serialize PHP variables, including objects, in JSON format. Support to unserialize it too.
Affected versions of this package are vulnerable to Deserialization of Untrusted Data via the JsonSerializer::unserialize() function. An attacker can execute arbitrary code or perform unauthorized actions by supplying crafted JSON input containing arbitrary classes with potentially dangerous magic methods.
Notes:
- Successful exploitation of this vulnerability requires the application or its dependencies contain classes that can be leveraged in a gadget chain.
- the fix introduces a
setAllowedClasses()function that should be configured with safe classes.
Workaround
This vulnerability can be mitigated by never deserializing untrusted JSON with unserialize, validating and sanitizing all JSON input before deserialization, and disabling @type-based object instantiation in the application logic.
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.