CVE-2017-20239 describes a cross-site scripting (XSS) vulnerability present in MDwiki versions 0.6.2 through 0.6.2. This flaw allows remote attackers to execute arbitrary JavaScript code by injecting malicious payloads into the location hash parameter. Successful exploitation could lead to session hijacking, defacement, or redirection to malicious websites, impacting user data and system integrity.
The primary impact of CVE-2017-20239 is the ability for an attacker to execute arbitrary JavaScript within the context of a victim's browser session. This can be leveraged to steal cookies, redirect users to phishing sites that mimic the MDwiki interface, or even modify the content displayed within the MDwiki application. Given MDwiki's potential use in internal documentation or knowledge bases, an attacker could potentially gain access to sensitive internal information or compromise user accounts with access to the system. The blast radius extends to all users who interact with a vulnerable MDwiki instance, particularly those who click on specially crafted URLs containing malicious JavaScript in the hash fragment.
CVE-2017-20239 was published on 2026-04-12. No public proof-of-concept (PoC) code has been widely reported, but the vulnerability's nature makes it relatively straightforward to exploit. The vulnerability is not currently listed on the CISA KEV catalog. Given the ease of exploitation and the potential impact, it's prudent to apply mitigations even in the absence of active exploitation reports.
Exploit Status
EPSS
0.03% (9% percentile)
CISA SSVC
CVSS Vector
The primary mitigation for CVE-2017-20239 is to upgrade to a patched version of MDwiki. Unfortunately, no patched version is currently available. As a workaround, implement strict input validation and output encoding on all user-supplied data, particularly the location hash parameter. Deploying a Web Application Firewall (WAF) with rules to detect and block JavaScript injection attempts in the URL hash can also provide a layer of defense. Monitor access logs for unusual patterns or suspicious URLs containing JavaScript code.
To resolve this vulnerability, update MDwiki to a patched version. Sanitize or escape the input of the location hash parameter to prevent the execution of malicious JavaScript code. Implement a Content Security Policy (CSP) to mitigate the impact of XSS attacks.
Vulnerability analysis and critical alerts directly to your inbox.
CVE-2017-20239 is a vulnerability in MDwiki versions 0.6.2–0.6.2 that allows attackers to inject malicious JavaScript code via the location hash, potentially leading to code execution in a user's browser.
If you are using MDwiki version 0.6.2, you are potentially affected by this XSS vulnerability. Upgrade is the recommended solution, but workarounds are available if upgrading is not immediately possible.
The recommended fix is to upgrade to a patched version of MDwiki. As no patch is available, implement input validation and output encoding, and consider a WAF.
While no widespread exploitation has been publicly reported, the vulnerability's nature makes it relatively easy to exploit, so proactive mitigation is advised.
Check the MDwiki project's website or GitHub repository for updates and advisories related to CVE-2017-20239.
Upload your dependency file and we'll tell you instantly if this and other CVEs hit you.