Freemius SDK <= 2.5.9 - Reflected Cross-Site Scripting via fs_request_get
Strategic Overview
- Status
- Patched in 1.5.3
- Affected Version
<= 1.5.2- CVSS
- 6.1Medium
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CVE
CVE-2023-33999
At a glance
CVE-2023-33999 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the WP Delicious WordPress plugin, affecting versions <= 1.5.2. It carries a CVSS score of 6.1 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.5.3; sites on affected versions should update now. Disclosed July 2023, reported by Rafie Muhammad.
Vulnerability Overview
The Freemius SDK for WordPress is vulnerable to Reflected Cross-Site Scripting via the ‘fs_request_get’ function in versions up to, and including, 2.5.9 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.
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.
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
WP Delicious <= 1.5.2 carries this weakness at fs_request_get, and reaching it takes a caller who can reach the endpoint. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.
Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For WP Delicious the fix is 1.5.3: builds <= 1.5.2 are affected, anything from 1.5.3 onward is not.
Remediation
Update to version 1.5.3, or a newer patched version
How WordSec helps
The attempt arrives as an ordinary request to WP Delicious: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: WP Delicious 1.5.3 closes this, and updating the plugin is the step that ends it.
- Firewall
- Alerts
External References
Related records
Same weakness class
- 6.4CVE-2026-15099: WP Delicious <= 1.10.2 Stored Cross-Site Scripting
CVE-2026-15099 - 6.4CVE-2025-58605: WP Delicious <= 1.8.7 Stored Cross-Site Scripting
CVE-2025-58605 - 6.4CVE-2025-54023: WP Delicious <= 1.8.4 Stored Cross-Site Scripting
CVE-2025-54023 - 6.4CVE-2024-43935: Delicious Recipes – WordPress Recipe Plugin Stored XSS
CVE-2024-43935
Other vulnerabilities in WP Delicious – Recipe Plugin for Food Bloggers (formerly Delicious Recipes)
- 8.8CVE-2025-11755: Delicious Recipes <= 1.9.0 Arbitrary File Upload
CVE-2025-11755 - 8.1CVE-2024-7626: WP Delicious Improper Path Validation to Authenticated
CVE-2024-7626 - 6.3CVE-2022-4974: Freemius SDK <= 2.4.2 Missing Authorization Checks
CVE-2022-4974 - 5.3CVE-2026-14305: WP Delicious Missing Authorization
CVE-2026-14305 - 5.3CVE-2026-39528: Delicious <= 1.9.5 Missing Authorization
CVE-2026-39528 - 4.3CVE-2025-67548: WP Delicious <= 1.9.1 Missing Authorization
CVE-2025-67548
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