Headline
CVE-2023-25154: XSS of ActivityPub URI
Misskey is an open source, decentralized social media platform. In versions prior to 13.5.0 the link to the instance to the sender that appears when viewing a user or note received through ActivityPub is not properly validated, so by inserting a URL with a javascript scheme an attacker may execute JavaScript code in the context of the recipient. This issue has been fixed in version 13.5.0. Users are advised to upgrade. Users unable to upgrade should not “view on remote” for untrusted instances.
Impact
ActivityPubを通して受け取ったユーザーやノートを表示する際に表示される送信元へインスタンスへのリンクが適切に検証されていないため、javascriptスキームを持つURLを挿入することで、クリックした際に任意のJavaScriptを実行するリンクを挿入ことができます。
The link to the instance to the sender that appears when viewing a user or note received through ActivityPub is not properly validated, so by inserting a URL with a javascript scheme, a link that executes any JavaScript when clicked can be You can insert a link that executes any JavaScript when clicked by inserting a URL with a javascript scheme.
Patches
13.5.0で修正されています。
This has been fixed in 13.5.0.
Workarounds
信頼できないインスタンスの「リモートで表示」を行わない。
Do not “view on remote” untrusted instances.
Credits
RyotaK [email protected]