CVE-2006-5791 in Elog Web Logbook
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in elogd.c in ELOG 2.6.2 and earlier allow remote attackers to inject arbitrary HTML or web script via (1) the filename for downloading, which is not quoted in an error message by the send_file_direct function, and (2) the Type or Category values in a New entry, which is not properly handled in an error message by the submit_elog function.
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Analysis
by VulDB Data Team • 04/26/2026
The CVE-2006-5791 vulnerability represents a critical cross-site scripting flaw in ELOG version 2.6.2 and earlier, specifically within the elogd.c component. This vulnerability stems from inadequate input sanitization and improper HTML escaping in error handling mechanisms, creating exploitable pathways for remote attackers to execute malicious scripts within victim browsers. The vulnerability affects the logging system's web interface where user inputs are not properly validated or escaped before being rendered back to users in error messages, thereby enabling persistent XSS attacks that can compromise user sessions and exfiltrate sensitive information.
The technical implementation of this vulnerability occurs through two distinct attack vectors that exploit improper input handling within the ELOG application's core functions. The first vector involves the filename parameter used during file downloads, where the send_file_direct function fails to properly quote the filename in error messages, allowing attackers to inject malicious HTML or JavaScript code that executes when users encounter error conditions. The second vector targets the Type or Category fields in new entry submissions, where the submit_elog function does not adequately sanitize these values before displaying them in error messages, creating another pathway for XSS exploitation. Both vectors demonstrate a fundamental flaw in the application's security architecture where user-controllable data flows directly into web output without proper sanitization or encoding mechanisms.
From an operational impact perspective, this vulnerability enables attackers to execute arbitrary scripts in the context of authenticated users' browsers, potentially leading to session hijacking, credential theft, and data manipulation within the ELOG system. The attack surface is particularly concerning as it affects core logging functionality where users might be prompted to interact with error messages during normal operations, increasing the likelihood of successful exploitation. The vulnerability's remote nature means attackers can exploit it without requiring local system access, making it particularly dangerous for web-based logging systems that handle sensitive operational data. According to CWE-79, this vulnerability directly maps to Cross-Site Scripting flaws in input handling, while the ATT&CK framework categorizes this as a web application attack vector under the T1190 technique for exploitation of web applications.
The mitigation strategies for CVE-2006-5791 should focus on implementing proper input validation and output encoding mechanisms throughout the application's error handling processes. All user-controllable inputs must be sanitized before being rendered in web contexts, with special characters properly escaped using appropriate encoding schemes such as HTML entity encoding. The fix should involve modifying the send_file_direct and submit_elog functions to ensure that all parameters are properly quoted and encoded before inclusion in error messages. Additionally, implementing a comprehensive content security policy and adopting a defense-in-depth approach that includes input validation at multiple layers of the application architecture would significantly reduce the risk of exploitation. Organizations should also consider upgrading to patched versions of ELOG or implementing web application firewalls to provide additional protection against similar vulnerabilities in legacy systems.