CVE-2023-4919 in iframe Plugin
Summary
by MITRE • 10/25/2023
The iframe plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `iframe` shortcode in versions up to, and including, 4.6 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level permission and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This was partially patched in version 4.6 and fully patched in version 4.7.
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Analysis
by VulDB Data Team • 04/10/2026
The vulnerability identified as CVE-2023-4919 affects the iframe plugin for WordPress, specifically targeting versions up to and including 4.6. This represents a critical stored cross-site scripting vulnerability that exploits the `iframe` shortcode functionality within the plugin. The flaw exists due to inadequate input sanitization mechanisms and insufficient output escaping measures that fail to properly validate or sanitize user-supplied data before processing. Attackers with contributor-level permissions or higher can leverage this vulnerability to inject malicious scripts into WordPress pages, creating a persistent threat that executes whenever users access the compromised content.
The technical exploitation of this vulnerability occurs through the manipulation of the iframe shortcode parameter, which allows authenticated attackers to inject malicious JavaScript code directly into the plugin's processing pipeline. The vulnerability stems from CWE-79, which categorizes cross-site scripting flaws as weaknesses in input validation and output escaping. When the plugin processes the iframe shortcode, it fails to properly sanitize the input parameters, allowing attackers to inject malicious payloads that are then stored within the WordPress database. These stored scripts become active when legitimate users access pages containing the compromised iframe shortcode, creating a vector for various malicious activities including session hijacking, credential theft, and redirection to malicious sites.
The operational impact of this vulnerability extends beyond simple script execution, as it enables attackers to perform a wide range of malicious activities within the context of the compromised WordPress site. Contributors and higher-level users typically have the ability to create and modify content, making this vulnerability particularly dangerous as it allows attackers to establish persistent backdoors within the site. The stored nature of the XSS means that the malicious scripts remain active even after the initial injection, continuously executing whenever affected pages are accessed. This vulnerability also aligns with ATT&CK technique T1566, which covers social engineering through malicious content injection, and T1190, which addresses exploitation of vulnerabilities in web applications through malicious code injection.
Mitigation strategies for CVE-2023-4919 involve immediate patching to versions 4.7 or later where the vulnerability has been fully addressed. Organizations should implement strict role-based access controls to limit contributor-level permissions to trusted users only, reducing the attack surface for potential exploitation. Additionally, administrators should conduct regular security audits of plugin installations and monitor for unauthorized content modifications. The patch in version 4.7 includes comprehensive input sanitization and output escaping mechanisms that properly validate all iframe shortcode parameters, addressing the root cause of the vulnerability. Security monitoring should also include detection of suspicious shortcode usage patterns and implementation of web application firewalls to prevent exploitation attempts. The vulnerability highlights the importance of proper input validation and output escaping practices in web application development, as outlined in OWASP Top 10 security principles and the CWE guidelines for preventing cross-site scripting vulnerabilities.