CVE-2026-27206

CVE-2026-27206 is a high-severity vulnerability with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

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.

Frequently asked questions

What is CVE-2026-27206?
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.
How severe is CVE-2026-27206?
CVE-2026-27206 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-27206 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-27206?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-27206 have an EU (EUVD) identifier?
Yes. CVE-2026-27206 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7724.
When was CVE-2026-27206 published?
CVE-2026-27206 was published on 2026-02-21 and last updated on 2026-06-17.

References

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