8.0 High

An insecure deserialization (PHP object injection) vulnerability exists in Mautic's handling of segment filters and custom field properties.

CVE-2026-115190

An insecure deserialization (PHP object injection) vulnerability exists in Mautic's handling of segment filters and custom field properties. Several code paths that read these stored values from the database deserialize them without restricting which PHP classes may be instantiated, instead of using Mautic's safe deserialization helper. An attacker who is able to store a crafted serialized value in these segment filter or custom field properties can cause arbitrary PHP objects to be instantiated when Mautic later processes the data, for example during segment evaluation, contact export, or custom field API requests. Combined with gadget chains available in Mautic's dependencies, this could allow an attacker to execute arbitrary code on the server, read, modify, or delete data stored in the Mautic instance, including contact data, and affect its availability. Exploitation requires high privileges or an existing ability to write to the affected stored data.

Assessment

CVSS: 8 (v3.1)
Severity: High
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 26 October 2026
Last updated: 26 October 2026
Weakness: CWE-502
Assigner: security@mautic.org

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

At the source

References

https://github.com/mautic/mautic/security/advisories/GHSA-5r63-8h35-j3mw

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