Vulnerability in Joinmastodon Mastodon
CVE-2025-62176
Mastodon is a free, open-source social network server based on ActivityPub. In Mastodon before 4.4.6, 4.3.14, and 4.2.27, the streaming server accepts serving events for public timelines to clients using any valid authentication token, even if those tokens lack the read:statuses scope. This allows OAuth clients without the read scope to subscribe to public channels and receive public timeline events. The impact is limited, as this only affects new public posts published on the public timelines and requires an otherwise valid token, but this may lead to unexpected access to public posts in a limited-federation setting. This issue has been patched in versions 4.4.6, 4.3.14, and 4.2.27. No known workarounds exist.
EPSS: 0.003 (16.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
Affected products
- Joinmastodon Mastodon
- Mastodon — versions >= 4.4.0-beta.1, < 4.4.6, >= 4.3.0-beta.1, < 4.3.14, < 4.2.27
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2025-62176?
- CVE-2025-62176 is a medium-severity vulnerability in Joinmastodon Mastodon, classified under Improper Handling of Insufficient Permissions or Privileges. CVSS score: 4.3/10. Published 2025-10-13.
- How severe is CVE-2025-62176?
- Medium severity. CVSS v3 base score is 4.3 out of 10.