CVE-2020-35129 is a critical-severity cross-site scripting (XSS) vulnerability in mautic/core (composer), affecting versions < 3.2.4. It is fixed in 3.2.4.
Mautic before 3.2.4 is affected by stored XSS. An attacker with access to Social Monitoring, an application feature, could attack other users, including administrators. For example, an attacker could load an externally drafted JavaScript file that would allow them to eventually perform actions on the target user’s behalf, including changing the user’s password or email address or changing the attacker’s user role from a low-privileged user to an administrator account.
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-2020-35129 has a CVSS score of 9.0 (Critical). The vector is network-reachable, low privileges required, and user interaction required. 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 (3.2.4). Upgrading removes the vulnerable code path.
composer
mautic/core (< 3.2.4)mautic/core → 3.2.4 (composer)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 instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2020-35129 is reachable in your applications. Explore open-source security for your team.
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Already deployed Kodem? See CVE-2020-35129 in your environment →Upgrade mautic/core to 3.2.4 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2020-35129 is a critical-severity cross-site scripting (XSS) vulnerability in mautic/core (composer), affecting versions < 3.2.4. It is fixed in 3.2.4. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
CVE-2020-35129 has a CVSS score of 9.0 (Critical). 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.
mautic/core (composer) versions < 3.2.4 is affected.
Yes. CVE-2020-35129 is fixed in 3.2.4. Upgrade to this version or later.
Whether CVE-2020-35129 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
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.
Upgrade mautic/core to 3.2.4 or later.