TI-2023-05118 Aliases CVE-2023-5560 GHSA-3v9m-2r3c-48wc

WP-UserOnline < 2.88.3 - Unauthenticated Stored XSS

MEDIUM 60CWE-79Published 2023-11-27 · Updated 2024-11-21

Key facts

Attack vector: Network
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: Cross-site scripting
Confidentiality · integrity · availability: Low · Low · None
Fix status: Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.0051 43rd percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by the CNA and NVD

Fix Fixed WP-UserOnline (Unknown): 2.88.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Unknown	WP-UserOnline	before 2.88.3	2.88.3	Patch available	CNA

WP-UserOnline VendorUnknown Affected before 2.88.3 Fixed in 2.88.3 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:lesterchan:wp-useronline::::::wordpress::*	before 2.88.3	Vulnerable	Lester Chan

cpe:2.3:a:lesterchan:wp-useronline:*:*:*:*:*:wordpress:*:* Versions before 2.88.3 Vulnerable ·Lester Chan

Remediation

Fix · CNA WP-UserOnline (Unknown) Fixed in 2.88.3

Timeline

2026-10-02 Threatist record created from CVE-2023-5560
2026-10-03 Alias added: GHSA-3v9m-2r3c-48wc

References

Exploit 1

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

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences