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Vulnerability record · CVE-2026-27206 · published 21 February 2026

CVE-2026-27206: Deserialization of untrusted data vulnerability

Zumba Json Serializer is a library to serialize PHP variables in JSON format. In versions 3.2.2 and below, the library allows deserialization of PHP objects from JSON using a special @type field. The deserializer instantiates any class specified in the @type field without restriction. When processing untrusted JSON input, this behavior may allow an attacker to instantiate arbitrary classes available in the application. If a vulnerable application passes attacker-controlled JSON into JsonSerializer::unserialize() and contains classes with dangerous magic methods (such as __wakeup() or __destruct()), this may lead to PHP Object Injection and potentially Remote Code Execution (RCE), depending on available gadget chains in the application or its dependencies. This behavior is similar in risk profile to PHP's native unserialize() when used without the allowed_classes restriction. Applications are impacted only if untrusted or attacker-controlled JSON is passed into JsonSerializer::unserialize() and the application or its dependencies contain classes that can be leveraged as a gadget chain. This issue has been fixed in version 3.2.3. If an immediate upgrade isn't feasible, mitigate the vulnerability by never deserializing untrusted JSON with JsonSerializer::unserialize(), validating and sanitizing all JSON input before deserialization, and disabling @type-based object instantiation wherever possible.

8.1 CVSS 3.1 High EPSS 1.0% · top 38.1% CWE-502 · Deserialization of untrusted data Deferred
8.1CVSS 3.1 base score
1.0%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
3References
17 Jun 2026Last modified by NVD

Description

Zumba Json Serializer is a library to serialize PHP variables in JSON format. In versions 3.2.2 and below, the library allows deserialization of PHP objects from JSON using a special @type field. The deserializer instantiates any class specified in the @type field without restriction. When processing untrusted JSON input, this behavior may allow an attacker to instantiate arbitrary classes available in the application. If a vulnerable application passes attacker-controlled JSON into JsonSerializer::unserialize() and contains classes with dangerous magic methods (such as __wakeup() or __destruct()), this may lead to PHP Object Injection and potentially Remote Code Execution (RCE), depending on available gadget chains in the application or its dependencies. This behavior is similar in risk profile to PHP's native unserialize() when used without the allowed_classes restriction. Applications are impacted only if untrusted or attacker-controlled JSON is passed into JsonSerializer::unserialize() and the application or its dependencies contain classes that can be leveraged as a gadget chain. This issue has been fixed in version 3.2.3. If an immediate upgrade isn't feasible, mitigate the vulnerability by never deserializing untrusted JSON with JsonSerializer::unserialize(), validating and sanitizing all JSON input before deserialization, and disabling @type-based object instantiation wherever possible.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

LinkTags
https://github.com/zumba/json-serializer/commit/bf26227879adefce75eb9651040d8982be97b881
https://github.com/zumba/json-serializer/releases/tag/3.2.3
https://github.com/zumba/json-serializer/security/advisories/GHSA-v7m3-fpcr-h7m2

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Source: NIST National Vulnerability Database (record CVE-2026-27206), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.