CVE-2018-25309 MyBB Recent threads 17.0 Persistent Cross-Site Scripting
Attackers can inject malicious scripts via thread subjects, executing arbitrary JavaScript in users' browsers viewing the index page.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2018-25309?
CVE-2018-25309 is a medium-severity cross-site scripting vulnerability in MyBB Recent threads, published on 29 Apr 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
MyBB Recent threads 17.0 contains a persistent cross-site scripting vulnerability that allows attackers to inject malicious scripts by creating threads with crafted subject lines. Attackers can create threads with script tags in the subject parameter to execute arbitrary JavaScript in the browsers of all users viewing the index page.
Weakness: CWE-79
Which versions are affected by CVE-2018-25309?
It affects 1 product.
Products include Dragonexpert Recent Threads on Index.
How do I fix CVE-2018-25309?
No fix has been published for CVE-2018-25309 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2018-25309 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-25309 exists.
Sources
Also known as GHSA-gcf4-8qvj-pjm9.