CVE-2023-40983 in Webmin
Summary
by MITRE • 09/15/2023
A reflected cross-site scripting (XSS) vulnerability in the File Manager function of Webmin v2.100 allows attackers to execute malicious scripts via injecting a crafted payload into the Find in Results file.
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Analysis
by VulDB Data Team • 01/30/2026
The vulnerability CVE-2023-40983 represents a critical reflected cross-site scripting flaw within Webmin version 2.100's File Manager component. This security weakness specifically manifests when users interact with the Find in Results functionality, creating an attack vector that enables remote code execution through malicious payload injection. The flaw resides in how the application processes and displays user-supplied input without adequate sanitization or encoding mechanisms, making it susceptible to XSS exploitation. This vulnerability affects the core administrative interface of Webmin, which is widely deployed for system administration tasks across various operating systems and network environments.
The technical implementation of this vulnerability follows the classic reflected XSS pattern where malicious scripts are injected into the application's response through user-controllable parameters. When an attacker crafts a specially formatted payload and injects it into the Find in Results field, the application fails to properly escape or filter the input before rendering it in the web interface. This allows the malicious script to execute within the context of the victim's browser session, potentially compromising user credentials, session data, or system access. The vulnerability is particularly concerning because it operates within the administrative interface of Webmin, which typically requires elevated privileges and provides access to critical system functions.
The operational impact of CVE-2023-40983 extends beyond simple script execution, as it can facilitate more sophisticated attacks within the compromised environment. An attacker could leverage this vulnerability to steal administrative sessions, modify system configurations, or escalate privileges within the Webmin interface. The reflected nature of the vulnerability means that attacks can be delivered through phishing emails, malicious links, or compromised websites that redirect users to the vulnerable Webmin instance. This makes the attack surface particularly broad as users may encounter the malicious payload in various contexts where they might be prompted to interact with the File Manager functionality. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications, and it maps to ATT&CK technique T1059.007 for script execution through web interfaces.
Mitigation strategies for CVE-2023-40983 should prioritize immediate patching of affected Webmin installations to version 2.101 or later, which contains the necessary security fixes. Organizations should also implement additional protective measures including input validation and output encoding controls within the web application layer, proper HTTP headers to prevent XSS attacks, and regular security assessments of web interfaces. Network-level protections such as web application firewalls can provide additional defense-in-depth measures, while user education regarding suspicious links and phishing attempts remains crucial. Security monitoring should focus on detecting unusual patterns in File Manager usage and unexpected script execution within administrative interfaces, as these activities may indicate exploitation attempts. The vulnerability demonstrates the critical importance of maintaining current software versions and implementing robust input sanitization practices in web-based administrative tools.