CVE-2021-27279 Cross-site scripting in n/a

Medium 5.4 Published 22 Feb 2021 Updated 3 Aug 2024

Attackers can inject malicious scripts via nested email tags in MyBB forums, potentially stealing user sessions or executing code.

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-2021-27279?

CVE-2021-27279 is a medium-severity cross-site scripting vulnerability in Mybb Mybb, published on 22 Feb 2021. 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 before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode).

Weakness: CWE-79

Which versions are affected by CVE-2021-27279?

It affects 1 product.

Products include Mybb Mybb.

How do I fix CVE-2021-27279?

No fix has been published for CVE-2021-27279 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-2021-27279 being exploited?

There is no known exploitation of CVE-2021-27279 in the wild and no public exploit code.

All Mybb Mybb vulnerabilities

Sources

Also known as GHSA-6483-hcpp-p75w.