CVE-2023-33495 in Craft
Summary
by MITRE • 06/20/2023
Craft CMS through 4.4.9 is vulnerable to HTML Injection.
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Analysis
by VulDB Data Team • 07/17/2025
The vulnerability identified as CVE-2023-33495 represents a significant security weakness in Craft CMS versions up to 4.4.9, specifically categorized as an HTML Injection flaw that can be exploited by malicious actors to compromise web applications. This vulnerability falls under the Common Weakness Enumeration framework as CWE-79, which defines the weakness of Cross-Site Scripting (XSS) due to improper neutralization of input data. The flaw manifests when user-supplied content or parameters are not adequately sanitized before being rendered in web pages, creating opportunities for attackers to inject malicious HTML code into the application's output.
The technical implementation of this vulnerability occurs within Craft CMS's content handling mechanisms where user inputs are processed and displayed without sufficient validation and sanitization measures. When administrators or users submit content containing HTML tags or script elements, the system fails to properly escape or filter these inputs before rendering them in the final web output. This allows attackers to inject malicious scripts or HTML code that can execute in the context of other users' browsers, potentially leading to session hijacking, credential theft, or further exploitation of the application.
The operational impact of this vulnerability extends beyond simple content manipulation, as it can enable sophisticated attack vectors that compromise the integrity and confidentiality of the affected system. Attackers can leverage this weakness to inject malicious scripts that can steal cookies, redirect users to phishing sites, or even execute arbitrary commands within the application context. The vulnerability particularly affects content management workflows where users with permissions to create or edit content can inadvertently or deliberately introduce malicious payloads that propagate through the CMS interface. This creates a persistent threat vector that can affect multiple users depending on the scope of the compromised content management system.
Mitigation strategies for CVE-2023-33495 require immediate attention through patch management and input validation improvements. Organizations should prioritize updating their Craft CMS installations to versions that address this vulnerability, typically those beyond 4.4.9 where the HTML injection protections have been implemented. Additional defensive measures include implementing comprehensive input sanitization routines that strip or escape HTML characters from user submissions, employing Content Security Policy (CSP) headers to limit script execution, and conducting regular security audits of content management workflows. The mitigation approach aligns with ATT&CK framework techniques related to input validation and privilege escalation, emphasizing the importance of securing data entry points and maintaining least privilege access controls. Security teams should also consider implementing web application firewalls to detect and block suspicious HTML injection attempts while monitoring for anomalous content submission patterns that may indicate exploitation attempts.