# CVE-2026-91011: EWWW Image Optimizer < 8.7.7 - Author+ Stored XSS via Image Class Attribute Backreference Expansion

> Authenticated authors can inject stored JavaScript via image attributes, leading to code execution in victim browsers.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H`)
- **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 available:** No
- **Published:** 17 Sep 2026
- **Updated:** 17 Sep 2026
- **Also known as:** GHSA-5c4g-pv82-qr56

## What is CVE-2026-91011?

CVE-2026-91011 is a medium-severity cross-site scripting vulnerability in Unknown EWWW Image Optimizer, published on 17 Sep 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

The EWWW Image Optimizer WordPress plugin before 8.7.7 does not properly escape image attribute values when it rewrites page output, allowing authenticated users with author-level access and above to inject arbitrary JavaScript that is stored in published content and executes in the browser of any user who later views the affected page.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-91011?


## How do I fix CVE-2026-91011?

No fix has been published for CVE-2026-91011 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-91011 being exploited?

There is no known exploitation of CVE-2026-91011 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-91011 and fix it if it is affected.

What it is: CVE-2026-91011 is a medium-severity cross-site scripting vulnerability in Unknown EWWW Image Optimizer, published on 17 Sep 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-91011 in the wild and no public exploit code.

Affected product: Unknown EWWW Image Optimizer. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-91011/ (Markdown: https://insights.sbomify.com/CVE-2026-91011/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-91011
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-91011
- OSV: https://osv.dev/vulnerability/CVE-2026-91011

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-91011/
Summaries are generated and may contain mistakes; the official description above is the record.