CVE-2025-26951 WordPress C9 Blocks plugin <= 1.7.7 - Cross Site Scripting (XSS) vulnerability
An attacker can execute arbitrary scripts in the context of other users via DOM-based XSS in the C9 Blocks WordPress plugin.
- 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-2025-26951?
CVE-2025-26951 is a medium-severity cross-site scripting vulnerability in covertnine C9 Blocks, published on 15 Apr 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
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in covertnine C9 Blocks c9-blocks allows DOM-Based XSS.This issue affects C9 Blocks: from n/a through <= 1.7.7.
Weakness: CWE-79
Which versions are affected by CVE-2025-26951?
How do I fix CVE-2025-26951?
No fix has been published for CVE-2025-26951 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-2025-26951 being exploited?
There is no known exploitation of CVE-2025-26951 in the wild and no public exploit code.
Sources
Also known as GHSA-99gc-fxf4-398x.