A cross-site scripting (XSS) vulnerability in the SEOmatic plugin 3.4.10 for Craft CMS 3 allows remote attackers to inject arbitrary web script via a GET to /index.php?action=seomatic/file/seo-file-link with url parameter containing the base64 encoded URL of a malicious web page / file and fileName parameter containing an arbitrary filename with the intended content-type to be rendered in the user’s browser as the extension.
github.com/nystudio107/craft-seomatic
github.com/nystudio107/craft-seomatic/blob/develop/CHANGELOG.md
github.com/nystudio107/craft-seomatic/commit/4e46b792ce973ac0c652fb330055f41aca1981c8
github.com/nystudio107/craft-seomatic/commit/5f2cdc7c39e0a4bfb60d2f84131508f0a87b2873
nvd.nist.gov/vuln/detail/CVE-2021-41750