SSRF in Joinmastodon Mastodon
CVE-2026-22245
Mastodon is a free, open-source social network server based on ActivityPub. By nature, Mastodon performs a lot of outbound requests to user-provided domains. Mastodon, however, has some protection mechanism to disallow requests to local IP…
Vulnerability class: SSRF (Server-Side Request Forgery)
EPSS: 0.002 (16.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Joinmastodon Mastodon
- Mastodon — versions < 4.2.29, >= 4.3.0-beta.1, < 4.3.17, >= 4.4.0-beta.1, < 4.4.11
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-22245?
- CVE-2026-22245 is a high-severity vulnerability in Joinmastodon Mastodon, classified under Server-Side Request Forgery (SSRF). CVSS score: 7.5/10. Published 2026-01-08.
- How severe is CVE-2026-22245?
- High severity. CVSS v3 base score is 7.5 out of 10.