CVE-2025-26778 in Gallery Plugin
Summary
by MITRE • 02/17/2025
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in NotFound Gallery allows Stored XSS. This issue affects Gallery: from n/a through 2.2.1.
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Analysis
by VulDB Data Team • 02/17/2025
The vulnerability identified as CVE-2025-26778 represents a critical cross-site scripting flaw within the NotFound Gallery web application, specifically categorized under CWE-79 Improper Neutralization of Input During Web Page Generation. This weakness enables attackers to inject malicious scripts into web pages viewed by other users, creating a persistent security risk that can compromise user sessions and data integrity. The vulnerability manifests as a stored XSS attack vector, meaning that malicious payloads are permanently stored on the server and executed whenever affected pages are rendered to users, rather than requiring immediate interaction with a malicious link.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization mechanisms within the gallery application's web page generation process. When users submit data through various input fields or parameters that are subsequently displayed on web pages, the application fails to properly escape or encode special characters that could be interpreted as HTML or JavaScript code. This flaw allows attackers to inject malicious scripts that can execute in the context of other users' browsers, potentially stealing session cookies, redirecting users to malicious sites, or performing unauthorized actions on behalf of victims. The vulnerability affects all versions of the Gallery application from the initial release through version 2.2.1, indicating a long-standing issue that has not been adequately addressed.
The operational impact of this stored XSS vulnerability extends beyond simple script execution, as it provides attackers with persistent access to user sessions and potentially sensitive information within the gallery environment. An attacker who successfully exploits this vulnerability can manipulate the gallery's display functionality to inject malicious code that executes whenever legitimate users view affected gallery pages. This creates a persistent threat vector where the malicious code remains active until the gallery is updated or the vulnerable input fields are cleared. The stored nature of the vulnerability means that the attack can affect multiple users over time, potentially compromising user accounts, stealing personal information, or redirecting traffic to malicious destinations. Security practitioners should note that this vulnerability aligns with ATT&CK technique T1531 for Establishing Persistence and T1059 for Command and Scripting Interpreter, as it enables long-term access and code execution within the application environment.
Mitigation strategies for CVE-2025-26778 should prioritize immediate remediation through input validation and output encoding mechanisms. Organizations using the NotFound Gallery application must implement comprehensive sanitization of all user-supplied input before it is stored or displayed in web pages. This includes implementing proper HTML encoding for all dynamic content, utilizing Content Security Policy headers to restrict script execution, and ensuring that all input fields undergo strict validation to prevent the injection of potentially dangerous characters. The application should also implement proper session management and authentication controls to limit the potential impact of successful XSS attacks. Additionally, regular security assessments and code reviews should be conducted to identify and address similar input validation vulnerabilities in other application components. Organizations should consider implementing web application firewalls and monitoring systems to detect and prevent exploitation attempts, while also ensuring that the gallery application is updated to the latest secure version once available. The vulnerability demonstrates the critical importance of input sanitization and output encoding in preventing XSS attacks, aligning with security best practices outlined in OWASP Top Ten and other industry standards for web application security.