title: HTML attributes when attaching a YouTube link to the post
description: Silverware Games is a social network where people can play games online. Users can attach URLs to YouTube videos, the site will generate related `<iframe>` when the post will be published. The handler has some sort of protection so non-YouTube links can't be posted, as well as HTML tags are being stripped. However, it was still possible to add custom HTML attributes (e.g. `onclick=alert("xss")`) to the `<iframe>'. This issue was fixed in the version `1.1.34` and does not require any extra actions from our members. There has been no evidence that this vulnerability was used by anyone at this time.
problem types: CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
affected:
{
vendor: mesosoi
product: silverwaregames-io-issue-tracker
versions:
version: < 1.1.34, status: affected
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: LOW
baseScore: 6.3
baseSeverity: MEDIUM
confidentialityImpact: LOW
integrityImpact: LOW
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
version: 3.1
]