CVE-2025-3581 Newsletter < 8.8.5 - Admin+ Stored XSS via Widget

Medium 4.8 Published Updated

Admins can inject malicious scripts via widget options in the Newsletter plugin, bypassing unfiltered_html restrictions in multisite setups.

Exploited in the wild
Not known
Login needed
An administrator
Attackable
Over the internet
Victim action needed
A user has to click or open something
Fix
None listed

What is CVE-2025-3581?

CVE-2025-3581 is a medium-severity cross-site scripting vulnerability in Unknown Newsletter, published on 9 Jun 2025. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

Official description

The Newsletter WordPress plugin before 8.8.5 does not validate and escape some of its Widget options before outputting them back in a page/post where the block is embed, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup).

Weakness: CWE-79

Which versions are affected by CVE-2025-3581?

It affects 1 product.

Products include Thenewsletterplugin Newsletter.

How do I fix CVE-2025-3581?

No fix has been published for CVE-2025-3581 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-2025-3581 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-3581 exists.

Sources

Also known as GHSA-f9xh-499r-w9qx.

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