Fluent Forms Pro Add On Pack <= 6.1.17 - Missing Authorization to Unauthenticated Arbitrary Attachment Deletion
Strategic Overview
- Status
- Patched in 6.1.18
- Affected Plugin
- Fluent Forms Pro Add On Pack
- Affected Version
<= 6.1.17- CVSS
- 6.5Medium
- Weakness type
- CWE-862 · Missing Authorization
- CVE
CVE-2026-2899
At a glance
CVE-2026-2899 is a medium-severity Missing Authorization vulnerability in the Fluent Forms Pro Add On Pack WordPress plugin, affecting versions <= 6.1.17. It carries a CVSS score of 6.5 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 6.1.18; sites on affected versions should update now. Disclosed March 2026, reported by Prickly Cactus.
Vulnerability Overview
The Fluent Forms Pro Add On Pack plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 6.1.17. This is due to the `deleteFile()` method in the `Uploader` class lacking nonce verification and capability checks. The AJAX action is registered via `addPublicAjaxAction()` which creates both `wp_ajax_` and `wp_ajax_nopriv_` hooks. This makes it possible for unauthenticated attackers to delete arbitrary WordPress media attachments via the `attachment_id` parameter. Note: The researcher described file deletion via the `path` parameter using `sanitize_file_name()`, but the actual code uses `Protector::decrypt()` for path-based deletion which prevents exploitation. The vulnerability is exploitable via the `attachment_id` parameter instead.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.
CWE-862: Missing Authorization
Fluent Forms Pro Add On Pack <= 6.1.17 carries this weakness at deleteFile(), and reaching it takes no account at all. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.
Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For Fluent Forms Pro Add On Pack the fix is 6.1.18: builds <= 6.1.17 are affected, anything from 6.1.18 onward is not.
Remediation
Update to version 6.1.18, or a newer patched version
How does WordSec protect against this?
This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: Fluent Forms Pro Add On Pack 6.1.18 closes this, and updating the plugin is the step that ends it.
- Login Security
- Alerts
External References
Related records
Same weakness class
Other vulnerabilities in Fluent Forms Pro Add On Pack
- 9.8CVE-2026-73532: Fluent Forms Pro 6.2.7 & Ninja Tables Pro 5.2.13 RCE
CVE-2026-73532 - 8.8CVE-2026-15962: Fluent Forms Pro Add On Pack PHP Object Injection
CVE-2026-15962 - 7.5CVE-2026-2428: Fluent Forms Pro Add On Pack Unauthenticated Payment
CVE-2026-2428 - 7.2CVE-2026-66633: Fluent Forms Pro Add On Pack < 6.2.12 Stored XSS
CVE-2026-66633 - 7.2CVE-2026-2365: Fluent Forms Pro <= 6.1.17 Stored Cross-Site Scripting
CVE-2026-2365 - 6.3CVE-2026-81297: Fluent Forms Pro Add On Pack Privilege Escalation
CVE-2026-81297 - 5.4CVE-2026-0632: Fluent Forms Pro Add On Pack <= 6.1.12 SSRF
CVE-2026-0632
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