CVE-2019-25502: Simplejobscript XSS Vulnerability

CVE-2019-25502 Overview

Simple Job Script contains a cross-site scripting (XSS) vulnerability that allows unauthenticated attackers to inject malicious scripts by manipulating the job_type_value parameter in the jobs endpoint. Attackers can craft requests with SVG payload injection to execute arbitrary JavaScript in victim browsers and steal session cookies or perform unauthorized actions.

Critical Impact

Unauthenticated attackers can execute arbitrary JavaScript in victim browsers, potentially stealing session cookies, performing unauthorized actions on behalf of users, or redirecting users to malicious websites.

Affected Products

• Simple Job Script (all versions)
• simplejobscript:simplejobscript

Discovery Timeline

• 2026-03-04 - CVE CVE-2019-25502 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2019-25502

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting (XSS). The flaw exists in the Simple Job Script application's handling of the job_type_value parameter within the jobs endpoint.

The application fails to properly sanitize user-supplied input before rendering it in the browser context. This allows attackers to inject malicious payloads, including SVG-based script injection techniques, which bypass basic filtering mechanisms. When a victim visits a crafted URL or interacts with a page containing the injected payload, the malicious JavaScript executes within their browser session.

The network-based attack vector means exploitation can occur remotely without any prior authentication. However, user interaction is required for successful exploitation—typically tricking a user into clicking a malicious link or visiting a compromised page.

Root Cause

The root cause of this vulnerability is insufficient input validation and output encoding in the Simple Job Script application. The job_type_value parameter is not properly sanitized before being reflected in the web page response, allowing attackers to inject HTML and JavaScript code that executes in the context of the victim's browser session.

Attack Vector

The attack is network-based and requires no authentication. An attacker can craft a malicious URL containing JavaScript payloads within the job_type_value parameter. When a victim clicks this link or visits a page containing the malicious request, the injected script executes within their browser. The attacker can leverage SVG elements to bypass certain XSS filters, as SVG tags can contain embedded script content that executes when rendered.

The vulnerability can be exploited through various techniques including:

• Direct script injection via the job_type_value parameter
• SVG payload injection that embeds malicious JavaScript within SVG tags
• Event handler injection using HTML attributes

Technical details regarding exploitation can be found in the Exploit-DB #46612 entry and the VulnCheck Security Advisory.

Detection Methods for CVE-2019-25502

Indicators of Compromise

• Suspicious requests to the jobs endpoint containing encoded JavaScript or SVG tags in the job_type_value parameter
• Web server logs showing URL-encoded script payloads such as %3Cscript%3E or %3Csvg
• Unusual session activity following user interaction with externally-sourced links
• Browser console errors indicating blocked inline script execution (if CSP is partially implemented)

Detection Strategies

• Monitor HTTP request logs for the job_type_value parameter containing HTML tags, JavaScript keywords, or encoded payloads
• Implement Web Application Firewall (WAF) rules to detect and block common XSS patterns in URL parameters
• Deploy browser-based security controls and Content Security Policy headers to mitigate script execution
• Review access logs for high volumes of requests to the jobs endpoint from suspicious IP addresses

Monitoring Recommendations

• Enable detailed logging for all requests to the Simple Job Script application, particularly the jobs endpoint
• Configure SIEM alerts for patterns indicative of XSS exploitation attempts
• Monitor for unusual patterns of session token usage that could indicate cookie theft
• Implement real-time alerting for requests containing script-related keywords in URL parameters

How to Mitigate CVE-2019-25502

Immediate Actions Required

• Apply input validation and output encoding to all user-supplied parameters, particularly job_type_value
• Implement Content Security Policy (CSP) headers to prevent inline script execution
• Deploy a Web Application Firewall with XSS protection rules enabled
• Review and sanitize all user input before rendering in HTML context

Patch Information

No official vendor patch information is currently available for this vulnerability. Organizations using Simple Job Script should implement the recommended workarounds and consider migrating to actively maintained job board software. For technical details, refer to the Exploit-DB #46612 entry and the VulnCheck Security Advisory.

Workarounds

• Implement server-side input validation to strip or encode HTML tags from the job_type_value parameter
• Add Content Security Policy headers to restrict inline script execution: Content-Security-Policy: default-src 'self'; script-src 'self'
• Configure Web Application Firewall rules to block requests containing script tags or SVG payloads
• Consider restricting access to the vulnerable endpoint until a permanent fix is available

# Example Apache configuration to add CSP headers
<IfModule mod_headers.c>
    Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'"
    Header set X-XSS-Protection "1; mode=block"
    Header set X-Content-Type-Options "nosniff"
</IfModule>