# CVE-2026-55690: EmbedVideo Extension: Stored XSS via unsanitized service name in exception text

> A user with edit permissions can inject stored JavaScript via unsanitized service names in error messages, leading to code execution for other visitors.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** GHSA-c29q-5xm7-5p62

## What is CVE-2026-55690?

CVE-2026-55690 is a high-severity cross-site scripting vulnerability in StarCitizenWiki mediawiki-extensions-EmbedVideo, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The EmbedVideo Extension is a MediaWiki extension which adds a parser function called #ev and various parser tags for embedding video clips from various video sharing services. Prior to 4.1.0, EmbedServiceFactory::newFromName in includes/EmbedService/EmbedServiceFactory.php interpolates an attacker-controlled unknown service name into exception text, and includes/EmbedVideo.php returns that text as HTML through the isHtml output path without neutralization. Both the #ev parser function and the evl parser form can reach this error path. A user able to edit a wiki page can inject stored HTML or JavaScript into the error output, causing code to execute in the wiki origin for visitors who render the page. This issue is fixed in version 4.1.0.

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

## Which versions are affected by CVE-2026-55690?

2 open source packages ship an affected version, including starcitizenwiki/embedvideo.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `starcitizenwiki/embedvideo` | Packagist | All versions | 4.1.0 |
| `starcitizenwiki/embedvideo` | Packagist | All versions | 4.1.0 |

## How do I fix CVE-2026-55690?

Upgrade starcitizenwiki/embedvideo to 4.1.0 or later.

## Is CVE-2026-55690 being exploited?

There is no known exploitation of CVE-2026-55690 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55690 and fix it if it is affected.

What it is: CVE-2026-55690 is a high-severity cross-site scripting vulnerability in StarCitizenWiki mediawiki-extensions-EmbedVideo, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-55690 in the wild and no public exploit code.

Affected packages and fixed versions:
- starcitizenwiki/embedvideo (Packagist): affected all versions; fixed in 4.1.0
- starcitizenwiki/embedvideo (Packagist): affected all versions; fixed in 4.1.0

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-2026-55690/ (Markdown: https://insights.sbomify.com/CVE-2026-55690/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55690
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55690
- OSV: https://osv.dev/vulnerability/CVE-2026-55690

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55690/
Summaries are generated and may contain mistakes; the official description above is the record.