CVE-2026-96578 in GSpeech TTS Plugin
Summary
by MITRE • 10/02/2026
The GSpeech TTS – WordPress Text To Speech Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content in all versions up to, and including, 3.22.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This mXSS-style transform bypasses WordPress comment kses sanitization because the payload is stored using only kses-allowed tags and attributes; the malicious event handlers and style fragments become active only when the plugin's output-buffer callback rewrites the rendered HTML at request time.
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Analysis
by VulDB Data Team • 10/02/2026
The GSpeech TTS – WordPress Text To Speech Plugin, specifically in versions up to 3.22.0, contains a critical security vulnerability classified as Stored Cross-Site Scripting within its comment handling functionality. This flaw stems from insufficient input sanitization and output escaping mechanisms that fail to adequately protect against malicious script injection. The vulnerability allows unauthenticated attackers to inject arbitrary web scripts into the application's data store by exploiting the comment content field. When a victim user subsequently accesses a page containing these injected comments, the embedded scripts execute within the context of the victim’s browser session, potentially leading to account compromise, session hijacking, or defacement depending on the privileges associated with the affected user accounts.
The technical nature of this vulnerability is particularly sophisticated as it represents an mXSS-style transform bypass rather than a traditional reflected XSS attack. The payload is carefully crafted using only tags and attributes that are permitted by WordPress’s default kses sanitization library, thereby evading initial filtering checks during data storage. However, the malicious event handlers and style fragments remain dormant until they are processed by the plugin's output-buffer callback function. This callback rewrites the rendered HTML at request time to integrate text-to-speech functionality, inadvertently activating the stored malicious code. By relying on this post-processing transformation step rather than direct rendering, the attacker bypasses standard security controls that typically sanitize content upon entry or initial display.
From an operational impact perspective, this vulnerability poses a significant risk to WordPress site administrators and their users because it requires no authentication for exploitation. An attacker can simply submit a comment containing the crafted payload on any public-facing page where comments are enabled. Once stored, every user who views that page becomes a potential target for the malicious script execution. This widespread exposure increases the likelihood of successful attacks compared to vulnerabilities requiring higher privilege levels or specific interaction sequences. The ability to execute arbitrary JavaScript in the context of the vulnerable site can lead to severe consequences including theft of sensitive information, redirection to phishing sites, and manipulation of user interactions without their knowledge.
To mitigate this vulnerability, immediate action is required by upgrading the GSpeech TTS plugin to a version that addresses these sanitization issues or disabling the plugin if it is not essential for current operations. Developers should implement strict output escaping using WordPress functions such as esc_html or wp_kses_post when rendering comment content within the text-to-speech transformation logic. It is crucial to ensure that any HTML rewriting processes do inadvertently introduce executable script elements by validating and sanitizing data both at input and output stages. Security best practices dictate applying defense-in-depth strategies, including Content Security Policy headers where applicable, to limit the impact of potential future exploits even if initial filtering mechanisms are bypassed.
This vulnerability aligns with CWE-79, which describes Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. Specifically, it illustrates a scenario where stored XSS payloads evade standard sanitizers through indirect execution paths involving dynamic HTML transformation. In terms of the MITRE ATT&CK framework, this exploit maps to techniques associated with Client-side Execution and potentially Command Line Interface if further exploitation chains are developed. Understanding these mappings helps security teams prioritize remediation efforts based on established industry standards for vulnerability management and risk assessment protocols.