Cyber Posture

CVE-2026-42754

High
Microsoft: not affectedMSmacOS: not affectedMacLinux: not affectedLnxMobile: not affectedMobNetwork: not affectedNetApplication: not affectedAppOther: affectedOth

Published: 27 May 2026

Published
27 May 2026
Modified
27 May 2026
KEV Added
—
Patch
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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 0.0003 10.2th percentile
Risk Priority 14 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-42754 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 10.2th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique.
Threat & Defense Details

Likely Mitigating ControlsAI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-79

Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.

SI-10 Information Input Validation
addresses: CWE-79

Validates web inputs to reject script-related content that could produce XSS.

SI-15 Information Output Filtering
addresses: CWE-79

Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.

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 →
T1539 Steal Web Session Cookie Credential Access
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials.
attack.mitre.org →
Why these techniques?

Reflected XSS in public-facing web plugin directly enables T1190 exploitation and T1539 session cookie theft via injected scripts.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in phbernard Favicon favicon-by-realfavicongenerator allows Reflected XSS.This issue affects Favicon: from n/a through <= 1.3.46.

Deeper analysisAI

Automated synthesis unavailable for this CVE.

Details

CWE(s)
CWE-79
OWASP Top 10 Web 2025
A05:2025

EU & UK References

References