What’s Vulnerable › Vulnerabilities

CVE-2023-5560: WP-UserOnline < 2.88.3 - Unauthenticated Stored XSS

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2023-11-27 · updated 2026-06-17
• Weakness: CWE-79

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.

Affected products

• WP-UserOnline: before 2.88.3 — fixed in 2.88.3

How to fix

Upgrade to a fixed version: WP-UserOnline 2.88.3. Check the vendor advisory for mitigations.

References

• https://wpscan.com/vulnerability/55d23184-fc5a-4090-b079-142407b59b05
• https://wpscan.com/vulnerability/55d23184-fc5a-4090-b079-142407b59b05

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