StarCitizenWiki Extension Embed Video: Stored XSS via unsanitized class passed to template

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.6 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

EPSS

• CVE-2026-55691: 0.48% estimated exploitation activity in the next 30 days; percentile 41.77 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The user supplied class value is fed directly into the sprintf call that creates HTML. You can add a quote to escape the class and then inject arbitrary html/javascript to the final output. Details The template here adds a figure with a class that is substituted in. This value is provided to sprintf here, an unescaped version of the class supplied by the user. PoC Note the double quote immediately following the single quote to escape the class attribute in the template: Impact Arbitrary HTML can be inserted into the DOM by any user on any page, allowing for JavaScript to be executed.

Published by the source

19 Jun 2026, 21:15 UTC

Last modified by the source

13 Oct 2026, 20:50 UTC

Source last checked

26 Oct 2026, 14:53 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7h5p-637f-jfr7

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# Patch Next advisory brief: CVE-2026-55691

Advisory: StarCitizenWiki Extension Embed Video: Stored XSS via unsanitized class passed to template
IDs: CVE-2026-55691, GHSA-7h5p-637f-jfr7
Record: https://patchnext.com/advisories/cve-2026-55691 (revision 1, source checked 26 Oct 2026, 14:53 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: starcitizenwiki/embedvideo 4.1.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist starcitizenwiki/embedvideo: affected <= 4.0.0; fixed in 4.1.0

## Suggested inspection (read-only)
- Packagist starcitizenwiki/embedvideo: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on starcitizenwiki/embedvideo.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7h5p-637f-jfr7 (GitHub-reviewed advisory GHSA-7h5p-637f-jfr7 lists affected ranges: Packagist starcitizenwiki/embedvideo >=0 <=4.0.0)

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