CVE-2023-5560
CWE-79Published: November 27, 2023· Updated: Jun 17, 2026
Official Description
The WP-UserOnline WordPress plugin before 2.88.3 does not sanitise and escape the X-Forwarded-For header before outputting its content on the page, which allows unauthenticated users to perform Cross-Site Scripting attacks.
Technical Analysis
CVE-2023-5560 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.
The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.
From a weakness classification perspective (CWE-79): Cross-site scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (2)
Quick Facts
Related CVEs (CWE-79)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2023-5560 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts