Log in / Sign up

Vulnerability details

CVE-2026-22245

mastodon mastodon

Mastodon has SSRF Protection bypass

CVSS 4.0
7.1High

Official description

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 addresses (unless specified in `ALLOWED_PRIVATE_ADDRESSES`) to avoid the "confused deputy" problem. The list of disallowed IP address ranges was lacking some IP address ranges that can be used to reach local IP addresses. An attacker can use an IP address in the affected ranges to make Mastodon perform HTTP requests against loopback or local network hosts, potentially allowing access to otherwise private resources and services. This is fixed in Mastodon v4.5.4, v4.4.11, v4.3.17 and v4.2.29.

CVSS scores

ScoreVersionSourceVector
7.1High 4.0 CVEProject cvelistV5 (CNA) (GitHub_M) CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Affected products

VendorProductVersionsSource
mastodon mastodon < 4.2.29 CVEProject cvelistV5 (CNA)
mastodon mastodon >= 4.3.0-beta.1, < 4.3.17 CVEProject cvelistV5 (CNA)
mastodon mastodon >= 4.4.0-beta.1, < 4.4.11 CVEProject cvelistV5 (CNA)
mastodon mastodon >= 4.5.0-beta.1, < 4.5.4 CVEProject cvelistV5 (CNA)

References and advisories

4
Kolun on Telegram @kolunsec Exploited CVEs, key news and a daily digest Alerts for this product's next CVEsFollow the product to get new vulnerabilities on Telegram.

Details

Published
2026-01-08
Last updated
2026-01-08
State
Published
Assigner (CNA)
GitHub_M

Exploit prediction (EPSS)

0.28%
Probability of exploitation in 30 days
21.5%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
No
Exploitation
None
Technical impact
Partial

Weaknesses (CWE)

  • CWE-918
    Server-Side Request Forgery (SSRF)