CVE-2026-104723

LifterLMS <= 10.2.1 - Authenticated (Custom+) PHP Object Injection via 'custom' Lesson Data

2026-10-09 17:20
Wordfence PRISM

Strategic Overview

Status
Patched in 10.3.0
Affected Version
<= 10.2.1
CVSS
8.8High
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2026-104723
View all LifterLMS – WP LMS for eLearning, Online Courses, & Quizzes vulnerabilities

At a glance

CVE-2026-104723 is a high-severity Deserialization of Untrusted Data vulnerability in the LifterLMS WordPress plugin, affecting versions <= 10.2.1. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account at Custom level or above. The issue is fixed in version 10.3.0; sites on affected versions should update now. Disclosed October 2026, reported by Wordfence PRISM.

Vulnerability Overview

The LifterLMS – WP LMS for eLearning, Online Courses, & Quizzes plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 10.2.1 via deserialization of untrusted input . This makes it possible for authenticated attackers, with custom-level access and above, to inject a PHP Object. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present. This vulnerability is only exploitable during lesson creation when a temporary lesson ID triggers the custom metadata path, and requires the attacker to hold a role with the edit_course capability, such as Instructor, Instructor's Assistant, LMS Manager, or Administrator.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-502: Deserialization of Untrusted Data

Reaching this weakness in LifterLMS <= 10.2.1 takes an account at Custom level or above. Deserialization of untrusted data means the application reconstructs objects from input a caller controls, letting the attacker choose which classes get instantiated and what their properties hold.

A workable chain turns deserialization into file writes, deletions or code execution, depending on what the loaded classes do in their magic methods. For LifterLMS the fix is 10.3.0: builds <= 10.2.1 are affected, anything from 10.3.0 onward is not.

Remediation

Update to version 10.3.0, or a newer patched version

How does WordSec protect against this?

An attacker needs Custom access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: LifterLMS 10.3.0 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C