CVE-2023-53978 myBB Forums 1.8.26 Stored Cross-Site Scripting via Forum Announcements
Authenticated administrators can inject malicious scripts into forum announcements, leading to arbitrary JavaScript execution for other users.
- 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-2023-53978?
CVE-2023-53978 is a medium-severity cross-site scripting vulnerability in Mybb Mybb, published on 22 Dec 2025. 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 Forums 1.8.26 contains a stored cross-site scripting vulnerability in the forum announcement system that allows authenticated administrators to inject malicious scripts when creating announcements. Attackers can exploit this vulnerability by inserting script payloads in the announcement title field when adding announcements through the 'Forums and Posts' > 'Forum Announcements' interface, causing arbitrary JavaScript to execute when the announcement is displayed on the forum.
Weakness: CWE-79
Which versions are affected by CVE-2023-53978?
It affects 1 product.
Products include Mybb Mybb.
How do I fix CVE-2023-53978?
No fix has been published for CVE-2023-53978 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-2023-53978 being exploited?
There is no known exploitation of CVE-2023-53978 in the wild and no public exploit code.
Other vulnerabilities in Mybb Mybb
Sources
Also known as GHSA-4hv2-45c6-qhf8.