Headline
GHSA-5pxh-89cx-4668: Magento LTS vulnerable to stored XSS in theme config fields
As reported by Aakash Adhikari, Github: @justlife4x4, the Design > Themes > Skin (Images / CSS) config field allows a Stored XSS when it contains an end script tag.
Impact
A malicious user with access to this configuration field could use a Stored XSS to affect other authenticated admin users in the admin panel.
The attack requires an admin user with configuration access, so in practice, it is not very likely to be used for gaining elevated privileges, although it could theoretically be used to impersonate other users.
Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.