CVE-2025-26557

High

Published: 03 March 2025

Published

03 March 2025

Modified

23 April 2026

KEV Added

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Patch

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CVSS Score v3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L

EPSS Score 0.0023 46.2th percentile

Risk Priority 14 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-26557 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 46.2th 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).

Deeper analysis

CVE-2025-26557 is an Improper Neutralization of Input During Web Page Generation vulnerability, classified as Reflected Cross-site Scripting (XSS) under CWE-79, in the ViperBar WordPress plugin developed by viperchill (also referenced as viperbar). This issue affects ViperBar versions from n/a through 2.0 inclusive, as published on 2025-03-03.

The vulnerability 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), indicating network accessibility, low attack complexity, no privileges required, and user interaction needed, with a changed scope leading to low impacts on confidentiality, integrity, and availability. Remote attackers can exploit it by crafting malicious inputs that reflect back unneutralized in web page generation, tricking authenticated or unauthenticated users into interacting with a malicious link or page to execute scripts in the victim's browser context.

The Patchstack advisory (https://patchstack.com/database/Wordpress/Plugin/viperbar/vulnerability/wordpress-viperbar-plugin-2-0-reflected-cross-site-scripting-xss-vulnerability?_s_id=cve) documents this Reflected XSS vulnerability specifically in ViperBar plugin version 2.0 for WordPress, providing details relevant to mitigation and patching for affected installations.

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2025-5615

Vulnerability details

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in viperchill ViperBar viperbar allows Reflected XSS.This issue affects ViperBar: from n/a through <= 2.0.

CWE(s): CWE-79

Related Threats

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.

attack.mitre.org →

T1059.007 JavaScript Execution

Adversaries may abuse various implementations of JavaScript for execution.

attack.mitre.org →

Why these techniques?

Reflected XSS in public-facing WordPress plugin directly enables T1190 (exploiting public-facing app via crafted malicious input/link) and T1059.007 (arbitrary JavaScript execution in victim's browser context).

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