CVE-2026-91827: Insecure Deserialization (CVSS 7.5)

Description

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.

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CVSS v3.1 Score

7.5

HIGH

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

EPSS — Exploit Prediction

0.0030

Probability of exploitation

0.21%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-502 Deserialization of Untrusted Data

References

Other References

https://wpscan.com/vulnerability/7b279db2-92e0-4122-b5c6-aa12b7b01858/

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-91827? +

CVE-2026-91827 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0030, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-91827? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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