CVE-2024-25623 Information

Description

Mastodon is a free open-source social network server based on ActivityPub. Prior to versions 4.2.7 4.1.15 4.0.15 and 3.5.19 when fetching remote statuses Mastodon doesn’t check that the response from the remote server has a Content-Type header value of the Activity Streams media type which allows a threat actor to upload a crafted Activity Streams document to a remote server and make a Mastodon server fetch it if the remote server accepts arbitrary user uploads. The vulnerability allows a threat actor to impersonate an account on a remote server that satisfies all of the following properties: allows the attacker to register an account; accepts arbitrary user-uploaded documents and places them on the same domain as the ActivityPub actors; and serves user-uploaded document in response to requests with an Accept header value of the Activity Streams media type. Versions 4.2.7 4.1.15 4.0.15 and 3.5.19 contain a fix for this issue.

Reference

https://github.com/mastodon/mastodon/security/advisories/GHSA-jhrq-qvrm-qr36 https://github.com/mastodon/mastodon/commit/9fee5e852669e26f970e278021302e1a203fc022