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CVE-2020-35129

CRITICAL

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,…

Published
Jan 19, 2021
Updated
Jun 17, 2026
Affected
0 pkgs
Patched
None yet
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
1.0%probability of exploitation in next 30 days
Lower Risk58th percentile+0.39%
0.12%0.58%1.04%1.51%0.6%1.0%Dec 25Apr 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

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.

Affected Products

1 product · 1 configurations
Application
mauticmautic
< 3.2.4
range

Detection & mitigation playbook

Vendor / appliance
  1. Detect

    Inventory every mautic mautic deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.

  2. Fix

    Apply the mautic mautic security patch or hotfix for CVE-2020-35129 on the affected version, following the vendor advisory for your exact build.

  3. Workarounds

    Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.

  4. How O3 protects you

    O3 detects and blocks CVE-2020-35129 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Tailored to CVE-2020-35129. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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.
O3 Security · Runtime Protection

Is CVE-2020-35129 being exploited in your environment?

O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2020-35129 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.