Summary
An issue was discovered in Moodle 3.x. An authenticated user is allowed to add HTML blocks containing scripts to their Dashboard; this is normally not a security issue because a personal dashboard is visible to this user only. Through this security vulnerability, users can move such a block to other pages where they can be viewed by other users.
Impact
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2018-1136 has a CVSS score of 4.3 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.1.12, 3.2.9, 3.3.6, 3.4.3); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
moodle/moodle to 3.1.12 or later; moodle/moodle to 3.2.9 or later; moodle/moodle to 3.3.6 or later; moodle/moodle to 3.4.3 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2018-1136? CVE-2018-1136 is a medium-severity cross-site scripting (XSS) vulnerability in moodle/moodle (composer), affecting versions >= 3.1, < 3.1.12. It is fixed in 3.1.12, 3.2.9, 3.3.6, 3.4.3. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2018-1136? CVE-2018-1136 has a CVSS score of 4.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of moodle/moodle are affected by CVE-2018-1136? moodle/moodle (composer) versions >= 3.1, < 3.1.12 is affected.
- Is there a fix for CVE-2018-1136? Yes. CVE-2018-1136 is fixed in 3.1.12, 3.2.9, 3.3.6, 3.4.3. Upgrade to this version or later.
- Is CVE-2018-1136 exploitable, and should I be worried? Whether CVE-2018-1136 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2018-1136 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2018-1136?
- Upgrade
moodle/moodleto 3.1.12 or later - Upgrade
moodle/moodleto 3.2.9 or later - Upgrade
moodle/moodleto 3.3.6 or later - Upgrade
moodle/moodleto 3.4.3 or later
- Upgrade