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GHSA-4j5h-mvj3-m48v

HighCVSS 8.6 / 10
Published Sep 24, 2025·Last modified Sep 26, 2025
Affected Components(0)

No affected components available

Description

Summary

The EmbedVideo extension allows adding arbitrary attributes to an HTML element, allowing for stored XSS through wikitext.

Details

The attributes of an iframe are populated with the value of an unreserved data attribute (data-iframeconfig) that can be set via wikitext: https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/blob/440fb331a84b2050f4cc084c1d31d58a1d1c202d/resources/ext.embedVideo.videolink.js#L5-L20 Similar code is also present here: https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/blob/440fb331a84b2050f4cc084c1d31d58a1d1c202d/resources/modules/iframe.js#L139-L155

It is possible to execute JS through attributes like onload or onmouseenter.

PoC

  1. Create a page with the following contents:
<div class="embedvideo-evl" data-iframeconfig='{"onload": "alert(1)"}'>Click me!</div>
<evlplayer></evlplayer>
  1. Click on the "Click me!" text
  2. Click on the "Load video" button below <img width="855" height="404" alt="image" src="https://github.com/user-attachments/assets/afb3839a-012c-4e90-a208-a6137b704ccd" />

Impact

Arbitrary HTML can be inserted into the DOM by any user, allowing for JavaScript to be executed.

Risk Scores
Base Score
8.6

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a low impact on the integrity of the data. There is a low impact on the availability of the system.

Threat Intelligence
7.9

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
0.28%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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High severity
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