CVE-2026-82773 in M2M Gateway
Summary
by MITRE • 09/14/2026
Cross-site scripting vulnerability exists in CONPROSYS M2M Gateway Series and CONPROSYS M2M Controller Series. If this vulnerability is exploited, an arbitrary script may be executed on a logged-in user's web browser.
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Analysis
by VulDB Data Team • 09/14/2026
The identified security flaw represents a classic Cross-Site Scripting (XSS) vulnerability affecting the web management interfaces of the CONPROSYS M2M Gateway and Controller series. This type of weakness typically arises when an application fails to properly validate, sanitize, or encode user-supplied input before including it in dynamically generated content sent back to the client's browser. In this specific context, the vulnerability allows an attacker to inject malicious scripts that are then executed within the security context of a logged-in administrator or operator session. The root cause lies in insufficient attention to output encoding and input validation mechanisms during the development of the device’s web server components, which treat untrusted data as executable code rather than inert text.
From a technical perspective, this vulnerability falls under CWE-79, known as Improper Neutralization of Input During Web Page Generation. The operational impact is severe because it targets authenticated users who have already bypassed initial access controls by providing valid credentials. Once an attacker successfully exploits the flaw, they can execute arbitrary JavaScript code in the victim's browser. This capability enables a range of malicious activities including session hijacking, where the attacker steals sensitive cookies or authentication tokens to impersonate the legitimate user; keylogging, which captures keystrokes entered into forms such as login pages or configuration fields; and credential harvesting through phishing-like interfaces injected directly into the trusted web page context. Furthermore, attackers may use this access to modify device configurations, redirect traffic, or pivot further into the internal network by leveraging the compromised session’s privileges.
The exploitation vector for this vulnerability is generally classified under ATT&CK technique T1059, specifically Command and Scripting Interpretation via JavaScript within a browser environment. It also aligns with MITRE CWE-834 regarding Excessive Trust in Received Data. The attack often requires social engineering elements to trick an authenticated user into clicking a malicious link or visiting a compromised webpage that contains the payload targeting the vulnerable parameter of the CONPROSYS interface. Because the script executes as if it originated from the trusted source, browser security policies such as the Same-Origin Policy do not prevent the execution, granting the attacker full access to all functionalities available to that user account at the time of exploitation.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. The primary defense is for the vendor to release a firmware update that implements strict input validation and output encoding on all affected parameters. Developers should ensure that any data reflected in HTML responses is properly encoded using context-aware techniques, such as HTML entity encoding for body content or JavaScript escaping for script blocks. Additionally, implementing Content Security Policy (CSP) headers can significantly reduce the impact of successful XSS attacks by restricting the sources from which scripts are allowed to load and execute. For operators currently running vulnerable versions, it is critical to enforce strong password policies, limit administrative access to trusted IP addresses where possible, and monitor web server logs for anomalous request patterns indicative of injection attempts until a patch can be applied. Regular security audits and penetration testing focused on input validation weaknesses are also recommended to prevent similar issues in future firmware releases.