CVE-2026-17567 (CVSS 5.3)

Description

The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 6.2.8 via the 'transaction' parameter due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to brute-force valid transaction hashes and view sensitive payment receipt data including customer name, email address, billing address, order items, payment method, and payment status belonging to other users. Because submission ID, form ID, and transaction creation time are either observable or guessable by an attacker, the effective brute-force space is bounded to approximately 900 candidates per second per (submission, form) pair, making exploitation practical without any prior authentication or account.

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CVSS v3.1 Score

5.3

MEDIUM

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

EPSS — Exploit Prediction

0.0038

Probability of exploitation

0.30%

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-639 CWE-639

References

Other References

https://plugins.trac.wordpress.org/browser/fluentform/tags/6.2.4/app/Modules/Payments/PaymentHandler.php#L218 https://plugins.trac.wordpress.org/browser/fluentform/tags/6.2.4/app/Modules/Payments/PaymentMethods/BaseProcessor.php#L959 https://plugins.trac.wordpress.org/browser/fluentform/tags/6.2.4/app/Modules/Payments/TransactionShortcodes.php#L107 https://plugins.trac.wordpress.org/browser/fluentform/tags/6.2.8/app/Modules/Payments/PaymentHandler.php#L218 https://plugins.trac.wordpress.org/browser/fluentform/tags/6.2.8/app/Modules/Payments/PaymentMethods/BaseProcessor.php#L959 https://plugins.trac.wordpress.org/browser/fluentform/tags/6.2.8/app/Modules/Payments/TransactionShortcodes.php#L107 https://plugins.trac.wordpress.org/changeset/3625751/fluentform/trunk/app/Modules/Payments/PaymentMethods/BaseProcessor.php https://plugins.trac.wordpress.org/changeset?old_path=%2Ffluentform/tags/6.2.8&new_path=%2Ffluentform/tags/6.2.9 https://www.wordfence.com/threat-intel/vulnerabilities/id/565980d7-8dc9-42a4-90c5-2f75af52fb8e?source=cve

Frequently Asked Questions

What is CVE-2026-17567? +

The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 6.2.8 via the 'transaction' parameter due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to brute-force valid transaction hashes and view sensitive payment receipt data including customer name, email address, billing address, order items, payment method, and payment status belonging to other users. Because submission ID, form ID, and transaction creation time are either observable or guessable by an attacker, the effective brute-force space is bounded to approximately 900 candidates per second per (submission, form) pair, making exploitation practical without any prior authentication or account. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-17567? +

CVE-2026-17567 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0038, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-17567? +

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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