Is CVE-2026-91827 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-91827 being exploited in the wild.

How severe is CVE-2026-91827?

High severity, with a CVSS score of 7.5, published 22 September 2026.

Is there a fix for CVE-2026-91827?

A patch was published on 2026-09-22: Fixed in version 3.15.4 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-91827 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-91827?

Check whether you run Ninja Forms at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-91827: Ninja Forms WordPress plugin PHP Object Injection in CSV export

CVE-2026-91827 · Severity: high · CVSS 7.5 · Published 2026-09-22

The Ninja Forms WordPress plugin, a form-building tool used on many websites, fails to properly validate user input during CSV export of form submissions. This allows unauthenticated attackers to inject malicious PHP objects that administrators will execute. If other vulnerable code (in plugins or themes) provides an attack chain, this can lead to arbitrary file deletion, modification, data theft, or remote code execution on the web server.

Technologies: Ninja Forms. Vendors: Ninja Forms.

Quick answers

Is CVE-2026-91827 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-91827 being exploited in the wild.
How severe is CVE-2026-91827?: High severity, with a CVSS score of 7.5, published 22 September 2026.
Which products and versions are affected?: Ninja Forms 3.15.3.
Is there a fix for CVE-2026-91827?: A patch was published on 2026-09-22: Fixed in version 3.15.4 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-91827 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-91827?: Check whether you run Ninja Forms at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The plugin deserializes untrusted user-submitted form field values during the CSV export process without proper sanitization, enabling PHP Object Injection (CWE-502). An unauthenticated attacker submits a form containing a serialized PHP object, and when an administrator exports submissions to CSV, the object is unserialized. Exploitation requires a PHP Object Injection gadget chain available in another installed plugin or theme, but the attack is network-accessible and requires no authentication on the attacker side.

Affected products

Ninja Forms Ninja Forms 3.15.3

Timeline

2026-09-22: disclosed
2026-09-22: patched: Fixed in version 3.15.4

References

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