Executive brief
Discuz! X5.0, a popular forum and community platform, contains a security flaw in its plugin management system. An attacker with administrative access can upload a malicious plugin configuration to trick the server into running unauthorized code. This could allow a compromised administrator account to take full control of the web server, potentially leading to data theft or a complete site shutdown.
Technical details
A Local File Inclusion (LFI) vulnerability exists in the plugin management functionality of Discuz! X5.0 (specifically within enable_disable.php). The root cause is insufficient validation of the 'directory' attribute during the plugin import process. An authenticated administrator can import a configuration containing path traversal sequences; by triggering an exception during installation, they can bypass sanitization routines and store malicious paths in the database. These paths are later passed to a PHP include() call. When combined with the ability to upload files, this allows for arbitrary PHP code execution in the context of the web server user. While this specific bug requires administrative privileges, researchers have demonstrated it can be chained with other flaws (like race conditions) to achieve pre-authentication remote code execution.
Affected products
- Discuz! Discuz! X5.0 20260320 through 20260610
Timeline
- 2026-04-27: other: Initial vendor contact attempt
- 2026-06-09: other: CVE identifier assigned
- 2026-06-13: disclosed: Public disclosure at hackmeeting 0x1D
- 2026-06-15: advisory: Publication of technical advisory