Deserialization in Ninja Forms
CVE-2026-91827
The Ninja Forms WordPress plugin 3.15.3 does not prevent user-submitted form field values from being deserialised when an administrator later exports form submissions to CSV, allowing unauthenticated attackers to perform PHP Object Injection; if a suitable POP chain is present via another installed plugin or theme, this can lead to actions such as arbitrary file operations or remote code execution.
Vulnerability class: Insecure Deserialization
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.
Affected products
- Unknown Ninja Forms
Weakness classification (CWE)
References
- contact@wpscan.com (technical-description, exploit, vdb-entry)
Frequently asked questions
- What is CVE-2026-91827?
- CVE-2026-91827 is a high-severity vulnerability in Ninja Forms, classified under Deserialization of Untrusted Data. CVSS score: 7.5/10. Published 2026-09-22.
- How severe is CVE-2026-91827?
- High severity. CVSS v3 base score is 7.5 out of 10.