Cyber Posture

CVE-2025-28917

High

Published: 26 March 2025

Published
26 March 2025
Modified
23 April 2026
KEV Added
Patch
CVSS Score 7.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
EPSS Score 0.0021 42.8th percentile
Risk Priority 14 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-28917 is a high-severity Cross-site Scripting (CWE-79) vulnerability. Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 42.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-15 (Information Output Filtering).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Directly addresses improper neutralization of input by validating smilie inputs to prevent storage of malicious XSS payloads.

prevent

Filters information outputs during web page generation to neutralize stored XSS scripts before execution in victims' browsers.

prevent

Ensures timely remediation and patching of the specific Stored XSS flaw in the Custom Smilies plugin up to version 2.9.2.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1189 Drive-by Compromise Initial Access
Adversaries may gain access to a system through a user visiting a website over the normal course of browsing.
Why these techniques?

Stored XSS in public-facing WordPress plugin directly enables T1190 (exploiting the web app vuln to inject payloads) and facilitates T1189 (drive-by compromise via malicious scripts executing in visitors' browsers).

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

NVD Description

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in crazyloong Custom Smilies custom-smilies-se allows Stored XSS.This issue affects Custom Smilies: from n/a through <= 2.9.2.

Deeper analysisAI

CVE-2025-28917 is an Improper Neutralization of Input During Web Page Generation vulnerability, classified as Stored Cross-site Scripting (XSS) under CWE-79, in the crazyloong Custom Smilies (custom-smilies-se) WordPress plugin. This issue affects all versions from n/a through 2.9.2. Published on 2025-03-26T15:16:16.803, it carries a CVSS v3.1 base score of 7.1 (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L).

Attackers can exploit this vulnerability remotely with low complexity and no required privileges, though it necessitates user interaction such as viewing a maliciously crafted page. By injecting payloads through the plugin's smilies functionality, adversaries can store scripts that execute in victims' browsers, achieving low impacts on confidentiality, integrity, and availability within a changed scope.

The Patchstack advisory at https://patchstack.com/database/Wordpress/Plugin/custom-smilies-se/vulnerability/wordpress-custom-smilies-plugin-2-9-2-cross-site-scripting-xss-vulnerability?_s_id=cve documents the Stored XSS vulnerability in Custom Smilies plugin version 2.9.2, providing details for WordPress administrators to address the issue.

Details

CWE(s)

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References