CVE-2026-91049EWWW Image Optimizer cross-site scripting
CVE-2026-91049 is a cross-site scripting in EWWW Image Optimizer, rated medium (6.4 on CVSS 3.1).
Why this priority: Medium severity, with no exploitation signal.
Published · Updated · NVD status: Deferred
What it is
Input is written into a web page without escaping, so an attacker's script runs in the browser of anyone who views it.
How it is reached
An attacker can exploit it over the network, with an administrator account, but someone has to act first, such as opening a file or following a link. Success also depends on conditions the attacker does not fully control.
What an attacker gains
A successful attack can read the data it protects, change data or behaviour and take it offline. In practice, this kind of flaw lets an attacker act inside a signed-in user's browser session.
Is it being exploited?
There is no public report of exploitation yet. EPSS estimates a 0.21% chance of exploitation activity in the next 30 days, higher than 11% of scored CVEs.
What to do
- Upgrade EWWW Image Optimizer to 8.9.1 or later.
- Until it is patched, review who holds accounts that can reach it.
- Warn the people who use it, and filter files and links on the way in.
Description from NVD
The EWWW Image Optimizer WordPress plugin before 8.9.1 does not properly sanitize and restrict a value in post content before using it to dynamically load and execute a script in the page, allowing authenticated attackers with author-level access and above to inject arbitrary web scripts that run in the session of any user who views the affected page, including administrators.
This is an incomplete fix of CVE-2026-15446: the origin and path restrictions added from 8.7.4 onward were each bypassable, so versions 8.7.4 through 8.9.0 remain affected.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- WordPress sites and their plugins. Plugins run inside the site with its database access, and many sites are public.
- Web front ends and single-page apps. The flaw sits between a user's browser and the web application.
- Admin consoles served to a browser. The flaw sits between a user's browser and the web application.
Trust boundaries in play
- Authenticated network access. An account is needed, so exposure follows who can sign in: customers, partners or staff.
- People who open files and links. Mail, chat and browsers are the delivery path.
- Between a user's browser and the web application. An attacker who crosses it can act inside a signed-in user's browser session.
Questions to answer about your own systems
- Where does EWWW Image Optimizer run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.