CVE-2024-25623: 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…

PriorityP348high7.7CVSS 3.1

AVNACLPRLUINSCCNIHAN

EPSS

0.52%

39.9th percentile

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.

Affected

8 ranges

Vendor	Product	Version range	Fixed in
joinmastodon	mastodon	< 3.5.19	3.5.19
joinmastodon	mastodon	>= 4.0.0 < 4.0.15	4.0.15
joinmastodon	mastodon	>= 4.1.0 < 4.1.15	4.1.15
joinmastodon	mastodon	>= 4.2.0 < 4.2.7	4.2.7
mastodon	mastodon	< 3.5.19	3.5.19
mastodon	mastodon	—	—
mastodon	mastodon	—	—
mastodon	mastodon	—	—

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