Arbitrary file upload in Joinmastodon Mastodon
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, 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.
Vulnerability class: Unrestricted File Upload
EPSS: 0.005 (41.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N.
Affected products
- Joinmastodon Mastodon
- Mastodon — versions < 3.5.19, >= 4.0.0, < 4.0.15, >= 4.1.0, < 4.1.15
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2024-25623?
- CVE-2024-25623 is a high-severity vulnerability in Joinmastodon Mastodon, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 8.5/10. Published 2024-02-19.
- How severe is CVE-2024-25623?
- High severity. CVSS v3 base score is 8.5 out of 10.
- Is CVE-2024-25623 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.