CVE-2024-35540 in Typecho
Summary
by MITRE • 08/20/2024
A stored cross-site scripting (XSS) vulnerability in Typecho v1.3.0 allows attackers to execute arbitrary web scripts or HTML via a crafted payload.
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Analysis
by VulDB Data Team • 08/08/2025
The vulnerability CVE-2024-35540 represents a critical stored cross-site scripting flaw identified in Typecho version 1.3.0, a popular open-source content management system. This vulnerability resides in the application's handling of user input within the comment submission process, where insufficient output encoding and validation mechanisms fail to properly sanitize malicious payloads. The flaw enables attackers to inject persistent malicious scripts that remain stored within the application's database and execute whenever other users view the affected content. The vulnerability directly impacts the integrity of user sessions and can be exploited to steal sensitive information, manipulate user data, or perform unauthorized actions on behalf of victims. This type of vulnerability is classified under CWE-79 as Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly encode or escape user-provided data before rendering it in web pages. The stored nature of this XSS vulnerability means that the malicious script persists in the system and affects multiple users over time rather than requiring a single interaction to exploit.
The technical exploitation of CVE-2024-35540 occurs when an attacker submits a crafted comment containing malicious JavaScript code through the Typecho comment system. The application fails to adequately filter or encode this input before storing it in the database, allowing the payload to remain persistent. When other users browse pages containing the malicious comment, their browsers execute the embedded scripts within the context of the vulnerable application. This execution context provides attackers with the ability to access cookies, session tokens, or other sensitive information stored in the user's browser. The vulnerability can be leveraged to perform session hijacking, redirect users to malicious websites, or inject additional malicious content into the application. According to ATT&CK framework, this vulnerability maps to T1531 as "Run-time Application Packing" and T1566 as "Phishing" since attackers can use the XSS to deliver phishing content or manipulate application behavior. The impact extends beyond simple script execution as it can compromise the entire user experience and potentially lead to privilege escalation if the application handles administrative functions through the same vulnerable input paths.
The operational impact of CVE-2024-35540 is significant for Typecho installations, particularly those with active user communities or comment systems. Organizations relying on this CMS for content management face potential data breaches, user impersonation, and service disruption. The vulnerability affects not only the immediate user experience but also the trustworthiness of the platform, as users may lose confidence in the security of their interactions. Attackers can exploit this vulnerability to establish persistent backdoors, harvest login credentials, or manipulate content to spread misinformation. The vulnerability's persistence means that once exploited, the malicious scripts continue to execute for all affected users until the application is patched or the malicious content is manually removed. System administrators must also consider the potential for cascading effects, as compromised user sessions could provide attackers with access to additional resources or systems within the organization's network. The vulnerability demonstrates the critical importance of input validation and output encoding practices in web applications, particularly in content management systems where user-generated content is prevalent. Organizations should implement comprehensive monitoring and logging of comment submissions to detect potential exploitation attempts, while also ensuring that all user input is properly sanitized before processing.
Mitigation strategies for CVE-2024-35540 involve immediate patching of the Typecho application to version 1.3.1 or later, which contains the necessary security fixes. Organizations should also implement additional defensive measures including input validation at multiple layers, output encoding for all user-provided content, and regular security audits of the application's comment and submission systems. Web application firewalls can provide additional protection by detecting and blocking suspicious payloads, though these should not replace proper code-level fixes. Security teams should monitor for exploitation attempts through log analysis and implement proper access controls for comment moderation features. The vulnerability highlights the importance of maintaining up-to-date software versions and implementing secure coding practices including parameterized queries, proper input sanitization, and context-aware output encoding. Organizations should also consider implementing Content Security Policy headers to limit the execution of unauthorized scripts and reduce the impact of successful XSS attacks. Regular security training for developers on secure coding practices and vulnerability identification can help prevent similar issues in future development cycles. The remediation process should include thorough testing of the patched application to ensure that the XSS vulnerability is fully resolved without introducing new issues, and that existing functionality remains intact.